Caffeic Research Articles

Synergistic Antioxidant and Anti-Inflammatory Effects of Phenolic Acid-Conjugated Glutamine-Histidine-Glycine-Valine (QHGV) Peptides Derived from Oysters (Crassostrea talienwhanensis).

The glutamine-histidine-glycine-valine (QHGV), a peptide derived from oysters, exhibits antioxidant activity and is being actively researched as a potential pharmaceutical and functional cosmetic ingredient. In this study, we synthesized the QHGV peptide and explored the hitherto unknown anti-inflammatory effects of QHGV. The antioxidant property was also characterized by conjugating with various naturally derived phenolic acids, such as caffeic, gallic, ferulic, sinapinic, and vanillic acids. Conjugation with phenolic acids not only enhanced the antioxidant activity of QHGV but also diminished the lipopolysaccharide-induced generation of reactive oxygen species (ROS) in the murine macrophage cell line, RAW 264.7. The reduction in the levels of reactive oxygen species led to the reduced mRNA expression of inducible nitric oxide synthase (iNos) and cyclooxygenase 2 (Cox-2), resulting in an anti-inflammatory effect through the inhibition of the phosphorylation of mitogen-activated protein kinase, including extracellular signal-activated protein kinase, c-Jun NH2-terminal kinase, and p38. Furthermore, the phenolic acid-conjugated peptides increased the mRNA and protein levels of collagen type I, indicative of a wrinkle-improvement effect. The phenolic acid conjugates of the peptide were not cytotoxic to human keratinocytes such as HaCaT cells. These results suggest that phenolic acid conjugation can enhance the potential of peptides as drug and cosmetic resources.

Influence of Abiotic and Biotic Elicitors on Organogenesis, Biomass Accumulation, and Production of Key Secondary Metabolites in Asteraceae Plants.

The medicinal plants of the Asteraceae family are a valuable source of bioactive secondary metabolites, including polyphenols, phenolic acids, flavonoids, acetylenes, sesquiterpene lactones, triterpenes, etc. Under stressful conditions, the plants develop these secondary substances to carry out physiological tasks in plant cells. Secondary Asteraceae metabolites that are of the greatest interest to consumers are artemisinin (an anti-malarial drug from Artemisia annua L.-sweet wormwood), steviol glycosides (an intense sweetener from Stevia rebaudiana Bert.-stevia), caffeic acid derivatives (with a broad spectrum of biological activities synthesized from Echinacea purpurea (L.) Moench-echinacea and Cichorium intybus L.-chicory), helenalin and dihydrohelenalin (anti-inflammatory drug from Arnica montana L.-mountain arnica), parthenolide ("medieval aspirin" from Tanacetum parthenium (L.) Sch.Bip.-feverfew), and silymarin (liver-protective medicine from Silybum marianum (L.) Gaertn.-milk thistle). The necessity to enhance secondary metabolite synthesis has arisen due to the widespread use of these metabolites in numerous industrial sectors. Elicitation is an effective strategy to enhance the production of secondary metabolites in in vitro cultures. Suitable technological platforms for the production of phytochemicals are cell suspension, shoots, and hairy root cultures. Numerous reports describe an enhanced accumulation of desired metabolites after the application of various abiotic and biotic elicitors. Elicitors induce transcriptional changes in biosynthetic genes, leading to the metabolic reprogramming of secondary metabolism and clarifying the mechanism of the synthesis of bioactive compounds. This review summarizes biotechnological investigations concerning the biosynthesis of medicinally essential metabolites in plants of the Asteraceae family after various elicitor treatments.

Quinic and caffeic acids derivatives: Affecting antioxidant capacities and phenolics contents of certain therapeutic and specialty crops employing water and ethanolic extracts

Recently, there has been a growing interest in medicinal and specialty crops due to their high content of health-promoting compounds, such as quinic acid and caffeic acid derivatives. In light of this, the objective of this study was to analyze the levels of caffeic and quinic acid, specifically caffeoylquinic acid derivatives, in water and water-ethanolic extracts obtained from medicinal plants, including chocolate mint (Mentha piperita L), lemon balm (Melissa officinalis), sweet basil (Ocimum basilicum), and sweet potato tops (Ipomoea batatas L. Lam) using high-performance liquid chromatography. The results showed that the water extracts contained significantly higher amounts of caffeoylquinic acid derivatives than the ethanolic extracts. Among the plants tested, sweetpotato leaves exhibited the highest total phenolic acids content (28.60 mg CQA·g−1), followed by lemon balm (14.71 mg CQA·g−1) and chocolate mint (5.49 mg CQA·g−1) in water-ethanolic extracts. The water-ethanolic extracts from sweet potato leaves were particularly rich in caffeoylquinic acids, especially 5-CQA (10.84 ± 0.31 mg CQA·g−1) and 3-CQA (6.69 ± 0.14 mg CQA·g−1), followed by lemon balm (3.81 ± 0.14 and 1.37 ± 0.05 mg CQA·g−1). On the other hand, sweet basil had the lowest content of all compounds (0.41 and 2.29 mg CQA·g−1). Additionally, an identifiable compound, 3, 4, 5 tri-caffeoylquinic acids (2.98 ± 0.09 mg CQA·g−1), was detected only in sweetpotato leaves and not in the other herbs studied. The findings of this study highlight the significant phytochemical properties present in these medicinal plants, which could have potential therapeutic applications for various conditions.

Unveiling the Antioxidant, Cytotoxic, and Anti-Inflammatory Activities and Chemical Compositional Information of an Invasive Plant: Lycium ferocissimum Miers.

In this study, the antioxidant (DPPH and ABTS radical-scavenging, ferric-reducing, iron (II)-chelating), anti-inflammatory (LPS-induced Raw 264.7 cell line), and cytotoxic activities (Du145 and A549 cell lines) of raw fruit, ripe fruit and leaves of the Lycium ferocissimum species were examined. By using high-pressure liquid chromatography, p-OH benzoic acid, caffeic acid, and rutin were detected in the ethanol and water extracts. For the most active raw fruit ethanol extract, the IC50 in terms of the DPPH-scavenging activity was 0.57 mg/mL, and the ABTS inhibition percentage was 88.73% at a 3 mg/mL concentration. The raw fruit ethanol extract exhibited significant inhibition of viability in the Du145 cell line in the concentration range of 62.5-1000 µg/mL. Additionally, the extract effectively reduced the LPS-induced inflammation parameters (TNF-α, IFN-γ, PGE 2, and NO) at a concentration of 31.25 µg/mL. The biological activities of L. ferocissimum, which have been elucidated for the first time, have yielded promising results.

Review on novel approaches for controlling aflatoxin B1: Harnessing nature's defenses against food toxins

Aflatoxin B1 is the most harmful food toxin for humans and animals. According to the International Agency for Research on Cancer, it is ranked as one of the most carcinogenic substances in the world, directly connected to hepatocarcinoma in both humans and animals. Aflatoxin B1 is also involved in the occurrence of pathologies, and aflatoxicoses. Aflatoxin B1 can be produced by fungi from the genus Aspergillus section Flavi in a variety of foods during storage. Once aflatoxins are present, food processing cannot eradicate them. The damage and lack of complete elimination of aflatoxins from foodstuffs make them the most monitored and controlled substances in the world. Given the high-risk of Aflatoxin B1 on both animal and human health, it is important to study their worldwide distribution and existing control methods through a systematic review. Articles published from 1945 to 2022 found on several databases as Scopus, PubMed, Dimensions, Google Scholar and an extraction sieve was used to select the relevant articles. Of the two hundred and twenty-eight (228) French and English scientific articles on aflatoxins identified, forty of the most relevant original articles were selected for inclusion in this review following a rigorous selection process. Several genes are involved in the synthesis of aflatoxin B1. Moreover, certain environmental conditions, in particular oxidative stress are propitious for fungus by over-expressing aflatoxins. However, the fungi defences can be controlled by several methods. Articles showed efficiency of various of them. Good cultural practices and awareness raising are part of the preventive control. Synthetic chemicals such as insecticides and fungicides are chronically used in chemical control of fungal growth and prevent aflatoxins from being produced. Biological control is based on allelic recombination between toxic and atoxic strains. The use of microbial competition is focused on the natural predators of aflatoxic molds, most often lactic acid bacteria, and the natural control relies on the use of natural plant substances. Natural substances like aqueous or organic plant extracts that contain proteins, polyphenols, tannins, antioxidants, flavonoids, terpenes, and chelating ion as well as caffeic acid, gallic acid and ascorbic acid can be used to control fungal contamination currently. These molecules interfere with free radicals to slow down or even inhibit the production of reactive oxygen species significantly reducing the production of aflatoxins making them inactive. Implementation of the means of controlling fungal growth and producing aflatoxins will help make agriculture globally competitive and ensure food security. Key words: Natural substances, Aflatoxin B1, food poisoning, alternative control, biocontrol

Clovamide and Its Derivatives-Bioactive Components of Theobroma cacao and Other Plants in the Context of Human Health.

Clovamide (N-caffeoyl-L-3,4-dihydroxyphenylalanine, N-caffeoyldopamine, N-caffeoyl-L-DOPA) is a derivative of caffeic acid, belonging to phenolamides (hydroxycinnamic acid amides). Despite a growing interest in the biological activity of natural polyphenolic substances, studies on the properties of clovamide and related compounds, their significance as bioactive components of the diet, as well as their effects on human health are a relatively new research trend. On the other hand, in vitro and in vivo evidence indicates the considerable potential of these substances in the context of maintaining human health or using them as pharmacophores. The name "clovamide" directly derives from red clover (Trifolium pratense L.), being the first identified source of this compound. In the human diet, clovamides are mainly present in chocolate and other cocoa-containing products. Furthermore, their occurrence in some medicinal plants has also been confirmed. The literature reports deal with the antioxidant, anti-inflammatory, neuroprotective, antiplatelet/antithrombotic and anticancer properties of clovamide-type compounds. This narrative review summarizes the available data on the biological activity of clovamides and their potential health-supporting properties, including prospects for the use of these compounds for therapeutic purposes.

Caffeic acid does not protect human pancreatic β cells against stearic acid‐induced ER stress and apoptosis

AbstractLong‐term elevation of saturated fatty acids in blood has a deleterious effect on pancreatic β‐cell function and survival, leading to endoplasmic reticulum (ER) stress and apoptosis. This fundamentally contributes to type 2 diabetes development. Caffeic acid (CA) was found to protect various cell types against several proapoptotic stimuli, including fatty acids. However, its potential protective effect against fatty acid‐induced apoptosis was not ascertained in pancreatic β cells yet. Therefore, the objective of this study was to examine this in the human pancreatic β‐cell lines NES2Y and 1.1B4. In both cell lines, CA did not modify the effect of saturated stearic acid (SA) on β‐cell growth and viability. At higher concentrations, CA significantly even intensified the adverse effect of SA. Consistent with this, CA did not exhibit any inhibitory effect on SA‐induced markers of ongoing apoptosis as well as ER stress. At higher concentrations, CA again slightly potentiated the effect of SA. CA applied alone was well tolerated up to 1 mM; however, at higher concentrations, it had detrimental effects in both cell lines. To conclude, we have shown that the treatment with caffeic acid has no inhibitory effect on SA‐induced ER stress and apoptosis in the human pancreatic β cells. Moreover, at higher concentrations, CA has proapoptotic potential.Practical applications: Caffeic acid exhibits a protective effect against saturated fatty acids in human hepatocytes. However, our data obtained with human β‐cell lines suggest that the potential usage of caffeic acid as a dietary component for the prevention and treatment of type 2 diabetes mellitus, developed with the contribution of saturated fatty acid‐induced apoptosis of β cells, seems rather unlikely.

Quality control methods for fruit extracts of Kigelia africana using high performance thin layer chromatography

Kigelia africana is a tree native to Africa but also found in eastern and southern parts of India with reported anti-bacterial, anti-inflammatory, and immunomodulatory activities. Verbascoside, caffeic acid and ferulic acid are important markers for the quality control of the plant. Two different HPTLC methods were developed and validated; method − 1 for estimation of verbascoside and caffeic acid while method − 2 for estimation of caffeic acid and ferulic acid. Developed methods were applied to the methanolic fruit extract to determine the quantities of markers. Both methods were found to be linear, specific, precise, accurate, sensitive and robust. Results indicated that both methods can be used for quantitative determination of verbascoside, caffeic acid and ferulic acid in fruit extract. The developed methods may be utilised as a part of the quality control and standardisation for the raw material and extracts of Kigelia africana and can also aid to chromatographic fingerprinting of the plant.

Antimicrobial and antiadhesive activities of secondary metabolites against Bacillus cereus adhesion on PLA 3D printing material: ADMET Tox in silico, molecular docking and molecular dynamic analysis

Bioactive compounds are naturally occurring substances that have the ability to have physiological impacts on the human body. Due to their potential health advantages and their function in preventing and treating a variety of serious health risks, also this substances shown a high antibacterial and antibiofilm activities against bacteria that can affect health. Therefore, the purpose of the current investigation was to test different bioactive compounds (Thymol, Quercetin, Epicatechin gallate, Gallic acid, Coumarin, Caffeic acid, Tannic acid, Apigenin, Carvacrol, Carvone, Beta ionone and Eucalyptol), in order to see there effect against B. cereus. Additionally, the contact angle method was used to examine the influence of those substances on the physicochemical characteristics of PLA 3D printing material and there antiadhesive effect against bacteria studied. According to the antibacterial activities it should be noted that Carvacrol, Tannic acid and Epicatechin gallate were the most active against B. cereus bacteria. The measurements of the contact angle showed a substantial change in the physicochemical characteristics of 3D printing PLA, indicating an improvement in the electron donor character after treatment, and significantly changed the surface hydrophobicity following treatment from hydrophobe PLA to hydrophile PLA after treatement, we can also see that B. cereus can adhere to PLA before treatment but after treatment with bioactive compounds it has become unfavorable which means that our select compounds are indeed active. After the use of computational methods like ADMET analysis, molecular docking and dynamic analysis, it was practical to better understand the physicochemical and pharmacokinetic proprieties, drug-likeness, antibacterial antiadhesive properties of the studied phytocomponents.

Plant-Derived Caffeic Acid and Its Derivatives: An Overview of Their NMR Data and Biosynthetic Pathways.

In recent years, caffeic acid and its derivatives have received increasing attention due to their obvious physiological activities and wide distribution in nature. In this paper, to clarify the status of research on plant-derived caffeic acid and its derivatives, nuclear magnetic resonance spectroscopy data and possible biosynthetic pathways of these compounds were collected from scientific databases (SciFinder, PubMed and China Knowledge). According to different types of substituents, 17 caffeic acid and its derivatives can be divided into the following classes: caffeoyl ester derivatives, caffeyltartaric acid, caffeic acid amide derivatives, caffeoyl shikimic acid, caffeoyl quinic acid, caffeoyl danshens and caffeoyl glycoside. Generalization of their 13C-NMR and 1H-NMR data revealed that acylation with caffeic acid to form esters involves acylation shifts, which increase the chemical shift values of the corresponding carbons and decrease the chemical shift values of the corresponding carbons of caffeoyl. Once the hydroxyl group is ester, the hydrogen signal connected to the same carbon shifts to the low field (1.1~1.6). The biosynthetic pathways were summarized, and it was found that caffeic acid and its derivatives are first synthesized in plants through the shikimic acid pathway, in which phenylalanine is deaminated to cinnamic acid and then transformed into caffeic acid and its derivatives. The purpose of this review is to provide a reference for further research on the rapid structural identification and biofabrication of caffeic acid and its derivatives.

Unravelling the metabolomic pool of Ocimum microgreens under diverse growing conditions through targeted compound analysis and non-targeted UHPLC-QToF-IMS based approach

Ocimum Sanctum L. (Basil) is a perennial herb belonging to the Lamiaceae family. The composition of microgreens is influenced by environmental conditions. Consequently, Ocimum microgreens were cultivated under varying growing conditions, assessing average height, total chlorophyll content, targeted compounds, and non-targeted UHPLC-QToF-IMS-based metabolomic profile. Under T3 growing condition (longer photoperiod of 22 h with 26 °C in light and 20 °C in the dark), Ocimum microgreens exhibited approximately 43% and 26% increases in average height and chlorophyll content, respectively. The targeted phenolic profile analysis identified gallic acid, caffeic acid, and resveratrol in microgreens. The growing conditions significantly influenced the phenolic profile. Also, sugar profiling indicated elevated levels of myo-inositol, glucose, fructose, sucrose, and d-raffinose under longer photoperiods with T3 conditions. Furthermore, microgreens exhibited a high abundance of amino acids such as aspartic acid, glutamic acid, proline, arginine, and phenylalanine. Notably, proline concentration increased from 13.40 mg/g to 25.15 mg/g in response to T3 growth condition. The comprehensive non-targeted UHPLC-QToF-IMS analysis revealed various metabolite classes, including organic compounds, phenolic and flavonoid derivatives, alkaloids, terpenoids, amino acids, sugars, polyalcohol and a few nucleic acid derivatives. Also, some organic acids, specifically rosmarinic acid, salvianolic acid D, and chicoric acid, showed highest expression level under T3 condition.

Effects of an inoculation dose of Issatchenkia terricola WJL-G4 on physicochemical properties, active substances, and antioxidant capacity of black, red, and white currant juice.

Due to the high level of organic acids - primarily citric acid - black, red, and white currants have an excessively sour taste, making taste adjustment during processing challenging. This study investigated and evaluated the effects of an inoculation dose of the acid-reducing yeast Issatchenkia terricola WJL-G4 on several aspect such as physicochemical properties, chromaticity, active substances, and antioxidant capacity. A sensory evaluation was also conducted. The results indicated that, when the inoculation dose increased from 2% to 12%, the total phenol, total flavonoid, and total anthocyanin content, and antioxidant capacity in currant juice decreased. A low inoculation dose (2-4%) was beneficial for preserving the total phenol and total flavonoid content. Although the levels of most phenolic compounds decreased, the concentrations of caffeic acid, p-coumaric acid, ferulic acid, rutin, and epicatechin were significantly higher than the control after fermentation. Overall acceptability and taste scores of fermented currants improved compared with those of the control group. This experiment provided an effective solution, with a theoretical basis, to the problems of the sour taste and harsh flavor of currant juice. © 2024 Society of Chemical Industry.

Polyphenol Profile, Antioxidant Activity and Yield of Cynara cardunculus altilis in Response to Nitrogen Fertilisation

Cardoon leaves are of great pharmaceutical importance due to their high content of polyphenol compounds. Polyphenolic compounds have attracted much interest due to their health-promoting effects. The content of these compounds in C. cardunculus depends on several factors, such as genotype, crop management, plant tissues, harvest time, and storage time. In this study, the effects of nitrogen (N) fertilisation (rates and forms) on the biomass yield and polyphenol profile of the leaves were determined. Increasing the amount of N up to 180 kg-ha−1 in fertilisation did not significantly increase the air-dried biomass yield of the leaves. On the contrary, it led to lower concentrations of total phenolic compounds (TP), total flavonoids (TF), caffeic acid, cynarin, and luteolin. Improvements in performance were achieved when 120 kg-ha−1 N rate was applied and increases in TP, TF content, and radical scavenging activity were observed. The applied N forms (NO3, NH4 or urea) had different effects on the concentrations of individual compounds and leaf air-dried biomass. Higher concentrations of cynarin, luteolin, and luteolin-7-O-glucoside were found when the N forms NH4 and urea were applied; higher caffeic acid content was found when urea was applied. The application of NO3 and urea in fertilisation reduced the level of luteolin-7-O-rutinoside, while the application of NO3 and NH4 reduced the amount of caffeic acid. The obtained results provide a better understanding of the effects of N rates and forms on cardoon leaves over two growing seasons.

Browning reactions of hydroxycinnamic acids and heterocyclic Maillard reaction intermediates – Formation of phenol-containing colorants

Non-enzymatic conversion of phenolic compounds plays an important role during thermal processing of plant-based food such as coffee, cocoa, and peanuts. However, the more prominent Maillard reaction is mainly studied at a mechanistic level for carbohydrates and amino compounds to clarify reactions that contribute to (‘classic') melanoidin formation, but the role of phenolic compounds in such reactions is rarely discussed yet. To understand their contribution to non-enzymatic browning, reactions between ubiquitous phenolic acids, such as caffeic acid and ferulic acid, and prominent heterocyclic Maillard intermediates, namely furfural, hydroxymethylfurfural, and pyrrole-2-carbaldehyde were investigated. Following incubation under roasting conditions (220 °C, 0–30 min), heterogenous products were characterized by high-resolution mass spectrometry, and, after isolation, by nuclear magnetic resonance spectroscopy. By this, color precursors were identified, and it was shown that in addition to aromatic electrophilic substitution, nucleophilic and condensation reactions are key mechanisms contributing to the formation of phenol-containing melanoidins.

Assessing the quality ecology of endemic tree species in China based on machine learning models and UPLC methods: The example of Eucommiaulmoides Oliv.

Climate change significantly affects the suitability distributions of natural populations, especially relict species such as Eucommia ulmoides Oliv. (E. ulmoides). However, the driving eco-factors of the distribution of E. ulmoides and the relationship between geo-distribution patterns and quality are still unclear. Here, a new approach was established by combining machine learning models (MaxEnt, Random Forest, and Biomod2 model), ultra-performance liquid chromatography (UPLC) and spatial analysis to address this question. The results reveal that temperature is the most critical variable influencing the distribution of E. ulmoides including Bio1, Bio10, and Bio11, followed by precipitation. Multi-model predictions of suitable habitats for E. ulmoides cover an area ranging from 113.33 × 104 km2 to 285.98 × 104 km2, mainly distributed in the mountainous areas of southwestern China, including the eastern regions of the Dalou, Wuling, and Qinling-Daba Mountains. Under different future scenarios, suitable habitat shifted northward by 184.90–424.88 km, and the contraction area is greater than the expansion area, with the difference ranging from 49.28 × 104 km2 to 98.39 × 104 km2. Eight common components (e.g., chlorogenic acid and pinoresinol doglucoside) and two endemic components (caffeic acid and geniposidic acid) were found in the leaves of the northern and southern medicinal districts (SDM and NMD). The contents of eight key secondary metabolites of E. ulmoides leaves were better distributed in SDM than in NDM. Among these, Xinyang in Henan, Lu'an and Fuyang in Anhui, and the southeastern region of Zhejiang are suitable growing areas for the high-quality cultivation of E. ulmoides, which deserve special attention. The seasonal precipitation (Bio15) was negatively correlated with chlorogenic acid and pinoresinol diglucoside while longitude significantly positively correlated with pinoresinol diglucoside. Overall, this study provides a novel assessment pattern for quality assessment and effective protection of E. ulmoides.

Increasing the robustness of Escherichia coli for aromatic chemicals production through transcription factor engineering

Engineering microbial cell factories has been widely used to produce a variety of chemicals, including natural products, biofuels, and bulk chemicals. However, poor robustness limits microbial production on an industrial scale. Microbial robustness is essential to ensure reliable and sustainable production of targeted chemicals. In this study, we developed an approach to screen transcription factors to improve robustness using CRSPRa technology. We applied this approach to identify some transcription factors to increase the robustness of Escherichia coli to aromatic chemicals. Activation of hdfR, yldP, purR, sosS, ygeH, cueR, cra, and treR increased the robustness of E. coli to phenyllactic acid. Upregulation of some transcription factors also improved the robustness to caffeic acid (cra) or tyrosol (cra, cueR, treR, soxS, hdfR and purR). Our study demonstrated that transcription factor engineering using CRISPRa is a powerful method to increase microbial robustness. This research provides new approaches to efficiently find genes responsible for increasing microbial robustness.

Preparation of robust structural color film on cotton fabrics by caffeic acid

Structural coloration holds significant promise for achieving ecological coloring of textiles. Caffeic acid, a natural plant polyphenol characterized by its cost-effectiveness, environmental friendliness, and non-toxic properties, has been identified as a key player in this context. It is found that caffeic acid can generate a polycaffeic acid (PCfA) nanofilm at the gas-liquid interface under certain conditions. In this work, caffeic acid was utilized to create thin film nanostructures by self-polymerization for the structural coloration of cotton fabrics, where the hue of the structural colors can be adjusted by polymerization time. Additionally, the incorporation of polyvinyl alcohol (PVA) into the system enhances the rubbing and washing fastness of the resultant structural colored fabric. The morphology of the structural color fabric was investigated by scanning electron microscopy (SEM), and the thickness of the films corresponding to the different colors were determined. This innovative approach presents a novel methodology for the development of robust structural color films.

Mechanisms of inhibition of advanced glycation product (AGE) and α-glucosidase by Heliotropium bacciferum: Spectroscopic and molecular docking analysis

Diabetes mellitus is characterized by hyperglycemia that makes insulin more prone to glycation and form advanced glycation end products (AGEs). Here, we report the effect of glyoxal (GO) on the formation of AGEs using human insulin as model protein and their structural modifications. The present investigation also reports the anti-AGE potential of Heliotropium bacciferum (Leaf) extracts. The phytochemical analysis of H. bacciferum revealed that free phenolic extract contains higher amount of total phenolic (3901.58 ± 17.06 mg GAE/100 g) and total flavonoid content (30.41 ± 0.32 mg QE/100 g) when compared to bound phenolic extract. Naringin and caffeic acid were identified as the major phenolic ingredients by UPLC-PAD method. Furthermore, bound phenolics extract showed significantly higher DPPH and superoxide radicals scavenging activity (IC50 17.53 ± 0.36 μg/mL and 0.306 ± 0.038 mg/ mL, respectively) (p ≤ 0.05). Besides, the bound phenolics extract also showed significant (p ≤ 0.05) chelating power (IC50 0.063) compared to free phenolic extract. In addition, bound phenolic extract could efficiently trap GO under physiological conditions. Spectroscopic investigation of GO-modified insulin illustrated changes in the tertiary structure of insulin and formation of AGEs. On the other hand, no significant alteration in secondary structure was observed by far UV-CD measurement. Furthermore, H. bacciferum extract inhibited α-glucosidase activity and AGEs formation implicated in diabetes. Molecular docking analysis depicted that GO bind with human insulin in both chains and forms a stable complex with TYR A: 14, LEU A:13, ASN B:3, SER A:12 amino acid residues with binding energy of – 2.53 kcal/mol. However, caffeic acid binds to ASN A:18 and GLU A:17 residues of insulin with lower binding energy of −4.67 kcal/mol, suggesting its higher affinity towards human insulin compared to GO. Our finding showed promising activity of H. bacciferum against AGEs and its complications. The major phenolics like caffeic acid, naringin and their derivatives could be exploited for the drug development for management of AGEs in diabetes.

Resistance Profile of Bacteria Isolated from Diabetic Wounds: Phytochemicals and Antibacterial Studies of Eriosema robustum Leaf Extracts

Diabetics are susceptible to severe trophic problems and wounds, which are frequently referred to as “unhealable wounds”. Untreated diabetic wounds provide an ideal habitat for the growth of bacteria, which can eventually develop resistance to standard treatments and need amputation. This study aimed to assess the in vitro antibacterial activity of ethanolic and aqueous extracts of Eriosema robustum leaves on the same bacterium, as well as the resistance profile of bacteria isolated from diabetic wounds to conventional antibiotics. Thirty samples from diabetic wounds were collected at the Baleveng Hospital, subjected to bacteria isolation and antibiotics resistance tests using the disk diffusion method. On the other hands, leaves of Eriosema robustum were collected, hydroethanolic extraction were performed. The extract obtained was used for the antibacterial (by determination of the MIC) and antioxidant (DPPH and FRAP tests) activities as well as phytochemicals composition (using HPLC methods) assessment.  Amon the 30 samples analyzed, 19 (63.33 %) showed bacterial infections and Staphylococcus aureus was the most common pathogen (48 %), followed by Pseudomonas aeruginosa (24 %), Klebsiella pneumoniae (19 %), and Streptococcus agalactiae (9 %). Fifty percent (50 %) of S. aureus isolates were MRSA (methicillin-resistant S. aureus). The MIC value obtained 64 μg/mL against S. aureus, Streptococcus agalactiae and Pseudomonas aeruginosa. Phytochemicals analysis of fractions from the 70 ° hydroethanolic leaves of Eriosema robustum revealed the presence of coumarin, gallic acid, quinoline, vanillin, ascorbic acid, caffeic acid, kaempferol, and cinnamic acid. The antibacterial and antioxidant potential of the extracts highlighted in this study could make this plant a good avenue for the discovery of new molecules effective against infected diabetic wounds. HIGHLIGHTS In this study, a total of 30 diabetic wounds were examined, and it was found that 63.33 % of them had infections. Staphylococcus aureus was the most frequently occurring bacteria, followed by Pseudomonas aeruginosa, Klebsiella pneumoniae, and Streptococcus agalactiae. The current study has revealed that, 96 % of the Staphylococcus aureus strains isolated were resistant to both tetracycline and methicillin, with the majority of the bacteria also showing resistance to amoxicillin. The hydroethanolic and aqueous extracts of Eriosema robustum displayed antibacterial activity against most of the isolated bacteria and the phytochemical analysis (HPLC) of fractions from the 70 ° hydroethanolic leaf extract revealed the presence of several secondary metabolites, including coumarin, gallic acid, quinoline, vanillin, ascorbic acid, caffeic acid, kaempferol, and cinnamic acid. This study opens up a new horizon in the management of diabetic wounds, and makes Eriosema robustum a potential candidate for the formulation of new drugs active against multi-resistant bacteria found in diabetic subjects. GRAPHICAL ABSTRACT

Evaluation of the antinociceptive activities of natural propolis extract derived from stingless bee Trigona thoracica in mice.

: Stingless bee propolis is a popular traditional folk medicine and has been employed since ancient times. This study aimed to evaluate the antinociceptive activities of the chemical constituents of aqueous propolis extract (APE) collected by Trigona thoracica in a nociceptive model in mice. : The identification of chemical constituents of APE was performed using high-performance liquid chromatography (HPLC). Ninety-six male Swiss mice were administered APE (400 mg/kg, 1,000 mg/kg, and 2,000 mg/kg) before developing nociceptive pain models. Then, the antinociceptive properties of each APE dose were evaluated in acetic acid-induced abdominal constriction, hot plate test, and formalin-induced paw licking test. Administration of normal saline, acetylsalicylic acid (ASA, 100 mg/kg, orally), and morphine (5 mg/kg, intraperitoneally) were used for the experiments. : HPLC revealed that the APE from Trigona thoracica contained p-coumaric acid (R2 = 0.999) and caffeic acid (R2 = 0.998). Although all APE dosages showed inhibition of acetic acid-induced abdominal constriction, only 2,000 mg/kg was comparable to the result of ASA (68.7% vs. 73.3%, respectively). In the hot plate test, only 2,000 mg/kg of APE increased the latency time significantly compared to the control. In the formalin test, the durations of paw licking were significantly reduced at early and late phases in all APE groups with a decrease from 45.1% to 53.3%. : APE from Trigona thoracica, containing p-coumaric acid and caffeic acid, exhibited antinociceptive effects, which supports its potential use in targeting the prevention or reversal of central and peripheral sensitization that may produce clinical pain conditions.