Tyrosinase Inhibition Assay Research Articles

Eco-friendly Synthesis of Gold Nanoparticles of Methanolic Extract of Bauhinia vahlii Leaves and Evaluation of Tyrosinase Inhibitory Activity

Background: The green synthesis of gold nanoparticles (AuNPs) using natural materials has gained significant attention in recent years due to their eco-friendliness and potential applications in various fields. Methods: The present study aimed at the green synthesis and anti-hyperpigmentation potential of gold nanoparticles (AuNPs) using a methanolic extract of Bauhinia vahlii. Furthermore, the green synthesis of the AuNPs was confirmed by UV-visible, FT-IR, XRD, and EMDEX analysis. The size and surface topological significance of green synthesized AuNPs were evaluated through Scanning Electron Microscope and Field Emission Scanning Electron Microscopy. Results: The size of the synthesized AuNPs was found to be in the range of 100-1000 nm. The tyrosinase inhibitory activity of AuNPs was evaluated through the mushroom tyrosinase inhibitory assay method. The tyrosinase inhibitory activities of crude extract, AuNPs, and Kojic acid were found to be 98.7 ±0.7, 75±1.3 and 41±1.1 μg/ml, respectively. Conclusion: Hence, green synthesized AuNPs of B. vahlii leaf extract may be used as a potent antihyperpigmentation agent in the market of nano cosmeceuticals.

Functional Properties and Components of Koenigia alpina Extract.

Koenigia alpina (All.) T.M.Schust. & Reveal (alpine knotweed) is a perennial herb belonging to the Polygonaceae family. Several studies have examined Polygonaceae species' potential applications as cosmeceutical materials; however, the potential of K. alpina as a cosmeceutical has not yet been studied. Hydrogen peroxide (H2O2) and lipopolysaccharide were used to induce an inflammatory response in RAW 264.7 cells. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radicals and H2O2 were used to evaluate the free-radical scavenging activity of K. alpina extract and its protective effect against reactive oxygen species (ROS)-induced cell damage. The whitening, antiaging, and cell proliferation/migration effects of the extracts were evaluated via tyrosinase inhibition, collagenase/elastase inhibition, and wound healing assays, respectively. The anti-inflammatory effect was confirmed by evaluating nitric oxide (NO) production in RAW 264.7 cells. High-performance liquid chromatography (HPLC), UV, and MS/MS were used to determine the main components of the extract and fractions. The ethyl acetate (EA) fraction and its aglycone fraction showed very high free-radical scavenging activities (47.5 and 47.1µg/mL, respectively). The extract/fractions also showed significant tyrosinase inhibition (IC50 = 0.38mg/mL in EA fraction), collagenase inhibition (IC50 = 0.21mg/mL in EA fraction), and elastase inhibition (IC50 = 0.57mg/mL in aglycone fraction). NO production in lipopolysaccharide-induced RAW 264.7 cells was inhibited by the extract/fractions. The extract also promoted the closure of scratch wounds in HaCaT cells. The K. alpina extract/fractions contained cardamonin, quercetin, and quercitrin. K. alpina extracts/fractions showed antioxidant, antiaging, whitening, and anti-inflammatory activities, suggesting they may have potential as antiaging cosmeceuticals.

Antioxidant and Antiaging Properties of Ethanolic Ripe Sesoot Fruit Extract

Skin aging can be characterized by changes in skin, such as the appearance of wrinkles and loss of skin moisture. Some elements that might lead to cell damages and aging are free radicals through the increase of the activities of hyaluronidase and tyrosinase. Bioactive compounds found in sesoot (Garcinia picrorhiza Miq.) are known for their antioxidant properties, which may reduce excessive amounts of free radicals in the body and act as an antiaging agent by inhibiting hyaluronidase and tyrosinase activities. This study aimed to examine the antioxidant, anti-hyaluronidase, and anti-tyrosinase properties found in Ethanolic Extract Ripe Sesoot (EERS). The ethanol extract of ripe sesoot fruit obtained from LIPI, Bogor Botanical Garden was used for the antioxidant and antiaging assays conducted at PT Aretha Medika Utama in December 2016. The activity of antioxidants was measured as the Ferric Reducing Antioxidant Power (FRAP) of the EERS, while the antiaging assays were performed through the inhibition activity of hyaluronidase and tyrosinase. Results indicated that the EERS has a higher FRAP activity (17.58 μM Fe (II)/μg) than xanthone (2.54 μM Fe (II)/μg) at the highest concentration of sample of 5,000 µg/mL. The anti-hyaluronidase of the EERS exhibited lower activity (IC50 of 619.21±12.15 µg/mL) than xanthone (IC50 of 365.55±25.10 µg/mL) and the tyrosinase inhibitory assay demonstrated a lower activity of EERS (IC50 of 1060.68±12.81 µg/mL) compared to xanthone (IC50 of 218.33±9.73 µg/mL). To conclude, EERS shows antioxidant and antiaging properties.

Synthesis, in vitro, and in silico study of novel pyridine based 1,3-diphenylurea derivatives as tyrosinase inhibitors

Tyrosinase inhibitors are studied in the cosmetics and pharmaceutical sectors as tyrosinase enzyme is involved in the biosynthesis and regulation of melanin, hence these inhibitors are beneficial for the management of melanogenesis and hyperpigmentation-related disorders. In the current work, a novel series of diphenyl urea derivatives containing a halo-pyridine moiety (5a–t) was synthesized via a multi-step synthesis. In vitro, tyrosinase inhibitory assay results showed that, except for two compounds, the derivatives were excellent inhibitors of human tyrosinase. The average IC50 value of the inhibitors (15.78 μM) is lower than that of kojic acid (17.3 μM) used as the reference compound, indicating that, on average, these molecules are more potent than the reference. Derivative 5a was identified as the most potent human tyrosinase inhibitor of the series, with an IC50 value of 3.5 ± 1.2 μM, approximately 5 times more potent than kojic acid. To get further insights into the nature of binding site interactions, molecular docking and molecular dynamics simulation studies were carried out. Moreover, the evaluation of in silico ADME properties showed a highly favorable profile for the synthesized compounds. These findings suggested that the further development of this class of compounds could be useful to get potent drug-like compounds that can target hyperpigmentation-related disorders.

New insights into the anti-inflammatory and anti-melanoma mechanisms of action of azelaic acid and other Fusarium solani metabolites via in vitro and in silico studies

Metabolites exploration of the ethyl acetate extract of Fusarium solani culture broth that was isolated from Euphorbia tirucalli root afforded five compounds; 4-hydroxybenzaldehyde (1), 4-hydroxybenzoic acid (2), tyrosol (3), azelaic acid (4), malic acid (5), and fusaric acid (6). Fungal extract as well as its metabolites were evaluated for their anti-inflammatory and anti-hyperpigmentation potential via in vitro cyclooxygenases and tyrosinase inhibition assays, respectively. Azelaic acid (4) exhibited powerful and selective COX-2 inhibition followed by fusaric acid (6) with IC50 values (2.21 ± 0.06 and 4.81 ± 0.14 μM, respectively). As well, azelaic acid (4) had the most impressive tyrosinase inhibitory effect with IC50 value of 8.75 ± 0.18 μM compared to kojic acid (IC50 = 9.27 ± 0.19 μM). Exclusive computational studies of azelaic acid and fusaric acid with COX-2 were in good accord with the in vitro results. Interestingly, this is the first time to investigate and report the potential of compounds 3–6 to inhibit cyclooxygenase enzymes. One of the most invasive forms of skin cancer is melanoma, a molecular docking study using a set of enzymes related to melanoma suggested pirin to be therapeutic target for azelaic acid and fusaric acid as a plausible mechanism for their anti-melanoma activity.

A comprehensive analysis on nutritional composition, functional properties, antioxidant and enzyme inhibitory potential of selected minor millet grains

Minor millets regarded as storehouse of proteins, dietary fibres, minerals, vitamins, fatty acids and phytochemicals have nutrigenomic role in human health. Determination of such components is an essential approach to choose highly efficient millet grains. Hence, this study has estimated and compared the mineral composition, proximates, functional properties, phytochemical and in vitro pharmacological properties of the seed grains of Setaria italica (Foxtail millet), Echinochloa frumentacea (Barnyard millet), Paspalum scrobiculatum (Kodo millet), and Panicum sumatrense (Little millet) cultivated in Kolli hills of Tamil Nadu, India. Mineral analysis revealed the presence of calcium, copper, magnesium, manganese, iron, phosphorus, potassium, and zinc. Occurrence of high content of protein, carbohydrate and vitamin E were also ascertained. The proximate composition (moisture, ash, crude lipid, and crude fibre) and functional features (water and oil absorbing capacity, bulk density, foaming and emulsifying property) of these millet flours have demonstrated their potential in food product formulation, particularly weaning foods. Total phenolic content was ranged between 53.28±0.71 and 110.42 ± 1.42 mg GAE g−1 of dried extract; and total flavonoid content was in the range of 23.80±1.09 to 65.1 ± 1.23 mg QE g−1 of dried extract in the studied millets. Significant free radical scavenging and enzyme inhibition activity was observed in P. sumatrense (IC50 of 128.92±1.18 µg mL−1 in DPPH assay), E. frumentacea (IC50 of 120.89±1.46 µg mL−1 in ABTS assay and 126.52±0.78 µg mL−1 in tyrosinase inhibition assay), S. italica (IC50 of 119.94±1.40 µg mL−1 in SO radical scavenging assay) and P. scrobiculatum (IC50 of 101.59±1.27 µg mL−1 in α-amylase enzyme inhibition assay and 94.63±0.78 µg mL−1 in α-glucosidase enzyme inhibition assay). The findings highlight the nutraceutical ability of these minor millets which can be employed as a valuable ingredient in food product preparation.

Bionic synthesis of novel monoterpenoid indole alkaloid-like analogs with tyrosinase inhibition activity based on loganetin

A series of novel monoterpenoid indole alkaloid (MIA)-like analogs (1–24) were synthesized by using a biomimetic synthetic strategy and combinatorial chemistry. The tyrosinase inhibitory activities and antioxidant properties of these compounds were assessed through tyrosinase inhibition assay, DPPH and ABTS free radicals scavenging assays, respectively. The results showed that most synthesized compounds (2, 4–8, 10–12, 14–17, 19) exhibited significant inhibitory activities against both monophenolase and diphenolase. In particular, compound 14, with an IC50 value of 0.18 ± 0.02 mM, displayed approximately 72-fold stronger monophenolase inhibitory activity than that of loganetin with an IC50 value of 12.76 ± 1.00 mM. Similarly, compound 17 exhibited the best diphenolase inhibitory activity (IC50, 0.30 ± 0.09 mM), which was approximately 47 times higher than that of loganetin (IC50, 14.05 ± 0.47 mM). Additionally, six compounds (3, 13–17) showed significant in vitro antioxidant activities. Compound 17 exhibited the most promising ABTS radical scavenging activity with an IC50 value of 2.90 ± 0.07 μM, while compound 15 exhibited the highest DPPH free radical scavenging capacity with an IC50 value of 17.59 ± 0.21 μM. The structure-activity relationships analysis revealed that the substituents at C-5 and C-11 in the tryptamine moiety might significantly impact antioxidant activity. Furthermore, the detailed interactions and binding modes of the most potent derivative toward tyrosinase were elucidated by a molecular docking study, which indicated that 14 and 17 might exert their inhibitory effects by binding to key amino acid residues (His 85 and His 263) at the tyrosinase active site.

Structural elucidation and development of azelaic acid loaded mesoporous silica nanoparticles infused gel: Revolutionizing nanodrug delivery for cosmetics and pharmaceuticals

This research aimed to enhance dermal delivery and optimize depigmentation therapy by designing mesoporous silica nanoparticles (MSNs) encapsulating azelaic acid (AZA) within a gel matrix. The MSNs were prepared using the sol-gel method. After subsequent processes, including acid extraction and drug loading, were then elucidated through PDI, size, zeta-potential, entrapment efficiency, nitrogen adsorption assay, FE-SEM, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and tyrosinase inhibition assay, were employed to assess the formulation. In-vitro stability tests for both AZA-MSN gel (AZCG) and AZA-loaded mesoporous silica gel (AZMG) were conducted at 8 °C, 25 °C, 40 °C, and 40 °C + 75 % RH, encompassing assessments of color, liquefaction, pH, and conductivity. Our findings showed a notable entrapment efficiency of 93.46 % for AZA-MSNs, with FE-SEM illustrating porous spherical MSNs. The particle size of AZA-MSNs was determined to be 211.9 nm, with a pore size of 2.47 nm and XRD analysis confirmed the amorphous state of AZA within the MSN carriers. Rheology examination indicated a non-Newtonian flow, while ex-vivo rat skin permeation studies conducted in a phosphate buffer (pH = 5.5) demonstrated a biphasic release pattern with 85.53 % cumulative drug permeation for AZA-MSNs. Overall, the study endorse the potential of AZA-MSNs as an efficacious and stable formulation for AZA delivery, highlighting their promise in addressing pigmentation concerns compared to conventional approaches.

Synthesis and evaluation of coumarin derivatives on antioxidative, tyrosinase inhibitory activities, melanogenesis, and in silico investigations

New coumarin derivatives were designed using a 2-(2-oxo-2H-chromen-4-yl)acetic acid scaffold conjugated with amino acid esters or tyramine. The anti-tyrosinase and anti-lipid peroxidation activities of the synthesized compounds were investigated. Coumarin derivatives 7,9, 11–13, 15–18 showed strong anti-lipid peroxidation activity. Compound 13 exhibited uncompetitive tyrosinase inhibitory activity with an IC50 value of 68.86 µM. Compound 14 (% activity = 123.41) showed stronger tyrosinase activating activity than 8-methoxypsolaren (8-MOP, % activity = 109.46). In silico studies revealed different poses between the inhibitors and activators near the tyrosinase catalytic site. Compounds 13 (25–50 μM) and 14 (25–100 μM) did not show cytotoxicity against B16F10 cells. In contrast to the tyrosinase inhibition assay, compound 13 (50 μM) suppressed melanogenesis in B16F10 cells with two times higher potency than KA (100 μM). Compound 14 at 100 μM showed melanogenesis enhancement in B16F10 cells in a dose-dependent manner, however, inferior to the 8-MOP. Based on the findings, compound 13 and 14 offer potential for development as skin-lightening agents and vitiligo therapy agents, respectively.

Pulp or Peel? Comparative Analysis of the Phytochemical Content and Selected Cosmetic-Related Properties of Annona cherimola L., Diospyros kaki Thumb., Cydonia oblonga Mill. and Fortunella margarita Swingle Pulp and Peel Extracts.

Fruit peels might be a valuable source of active ingredients for cosmetics, leading to more sustainable usage of plant by-products. The aim of the study was to evaluate the phytochemical content and selected biological properties of hydroglycolic extracts from peels and pulps of Annona cherimola, Diospyros kaki, Cydonia oblonga, and Fortunella margarita as potential cosmetic ingredients. Peel and pulp extracts were compared for their antiradical activity (using DPPH and ABTS radical scavenging assays), skin-lightening potential (tyrosinase inhibitory assay), sun protection factor (SPF), and cytotoxicity toward human fibroblast, keratinocyte, and melanoma cell lines. The total content of polyphenols and/or flavonoids was significantly higher in peel than in pulp extracts, and the composition of particular active compounds was also markedly different. The HPLC-MS fingerprinting revealed the presence of catechin, epicatechin and rutoside in the peel of D. kaki, whereas kaempferol glucoside and procyanidin A were present only in the pulp. In A. cherimola, catechin, epicatechin and rutoside were identified only in the peel of the fruit, whereas procyanidins were traced only in the pulp extracts. Quercetin and luteolinidin were found to be characteristic compounds of F. margarita peel extract. Naringenin and hesperidin were found only in the pulp of F. margarita. The most significant compositional variety between the peel and pulp extracts was observed for C. oblonga: Peel extracts contained a higher number of active components (e.g., vicenin-2, kaempferol rutinoside, or kaempferol galactoside) than pulp extract. The radical scavenging potential of peel extracts was higher than of the pulp extracts. D. kaki and F. margarita peel and pulp extracts inhibited mushroom and murine tyrosinases at comparable levels. The C. oblonga pulp extract was a more potent mushroom tyrosinase inhibitor than the peel extract. Peel extract of A. cherimola inhibited mushroom tyrosinase but activated the murine enzyme. F. margarita pulp and peel extracts showed the highest in vitro SPF. A. cherimola, D. kaki, and F. margarita extracts were not cytotoxic for fibroblasts and keratinocytes up to a concentration of 2% (v/v) and the peel extracts were cytotoxic for A375 melanoma cells. To summarize, peel extracts from all analyzed fruit showed comparable or better cosmetic-related properties than pulp extracts and might be considered multifunctional active ingredients of skin lightening, anti-aging, and protective cosmetics.

Chemical composition, enzyme inhibitory activities, and molecular docking studies of essential oil of Knema globularia leaves from Vietnam

In the present work, chemical composition, enzyme inhibitory activities, and molecular docking studies of essential oil (EO) of Knema globularia leaves collected from Vinh Phuc Province, Vietnam, were investigated. The EO from the leaves of K. globularia was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS) analysis. The leaf EO yield was 0.14 ± 0.01% (w/w), comprising 39 identified components, constituting 96.77% of the EO content. Notable constituents included β-caryophyllene (54.11%), α-humulene (12.67%), and (E)-β-ocimene (8.82%). Enzyme inhibitions were assessed via the α-amylase inhibitory assay (IC50 = 282.71 ± 10.06 μg/mL) and tyrosinase inhibitory assay (IC50 = 993.92 ± 37.40 μg/mL). The molecular docking method has been employed to observe valuable binding interactions and binding energy with the main compounds on the target enzymes α-amylase and tyrosinase. Caryophyllene oxide exhibits the strongest affinity with α-amylase among the other major compounds. Meanwhile, viridiflorene shows the best binding energy with the tyrosinase enzyme. This is the first study providing valuable scientific data on the in vitro inhibitory activities of α-amylase and tyrosinase enzymes of the leaf EO of K. globularia and evaluating its main compounds through a molecular docking approach on these enzyme targets.

African Under-Utilized Medicinal Leafy Vegetables Studied by Microtiter Plate Assays and High-Performance Thin-Layer Chromatography-Planar Assays.

Biological activities of six under-utilized medicinal leafy vegetable plants indigenous to Africa, i.e., Basella alba, Crassocephalum rubens, Gnetum africanum, Launaea taraxacifolia, Solanecio biafrae, and Solanum macrocarpon, were investigated via two independent techniques. The total phenolic content (TPC) was determined, and six microtiter plate assays were applied after extraction and fractionation. Three were antioxidant in vitro assays, i.e., ferric reducing antioxidant power (FRAP), cupric reduction antioxidant capacity (CUPRAC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, and the others were enzyme (acetylcholinesterase, butyrylcholinesterase, and tyrosinase) inhibition assays. The highest TPC and antioxidant activity from all the methods were obtained from polar and medium polar fractions of C. rubens, S. biafrae, and S. macrocarpon. The highest acetyl- and butyrylcholinesterase inhibition was exhibited by polar fractions of S. biafrae, C. rubens, and L. taraxacifolia, the latter comparable to galantamine. The highest tyrosinase inhibition was observed in the n-butanol fraction of C. rubens and ethyl acetate fraction of S. biafrae. In vitro assay results of the different extracts and fractions were mostly in agreement with the bioactivity profiling via high-performance thin-layer chromatography-multi-imaging-effect-directed analysis, exploiting nine different planar assays. Several separated compounds of the plant extracts showed antioxidant, α-glucosidase, α-amylase, acetyl- and butyrylcholinesterase-inhibiting, Gram-positive/-negative antimicrobial, cytotoxic, and genotoxic activities. A prominent apolar bioactive compound zone was tentatively assigned to fatty acids, in particular linolenic acid, via electrospray ionization high-resolution mass spectrometry. The detected antioxidant, antimicrobial, antidiabetic, anticholinesterase, cytotoxic, and genotoxic potentials of these vegetable plants, in particular C. rubens, S. biafrae, and S. macrocarpon, may validate some of their ethnomedicinal uses.

Cyrene™ as a tyrosinase inhibitor and anti-browning agent

The tyrosinase pathway takes part in the enzymatic process of food browning and is primarily responsible for food spoilage - manifesting itself from a decrease in its nutritional value to a deterioration of taste, which consequently leads to a gradual loss of shelf life. Finding safe and bio-based tyrosinase inhibitors and anti-browning agents may be of great importance in agriculture and food industries. Herein, we showed that Cyrene™ exhibits tyrosinase inhibitory activity (IC50: 268.2 µM), the 1.44 times higher than ascorbic acid (IC50: 386.5 μM). Binding mode studies demonstrated that the carbonyl oxygen of Cyrene™ coordinates with both copper ions. Surprisingly, both hydroxyl groups of Cyrene gem-diol perform a monodentate binding mode with both copper ions, at similar distances. This fact suggests that both compounds could have a similar binding mode and, as consequence, similar biological activities in tyrosinase inhibition assays and anti-browning activities.

Whitening Effect of Thinned Immature Apple Mango (Mangifera indica L. Irwin) Extract

Purpose: To evaluate the whitening activity of thinned immature apple mango (<i>Mangifera indica</i> L. Irwin) extract (TME).Methods: The study conducted tyrosinase inhibition assays and cytotoxicity evaluations and analyzed melanin production inhibition in B16F10 cells. Furthermore, the study examined the effects of TME treatment on the mRNA levels of tyrosinase (<i>TYR</i>), tyrosinase-related protein-1 (<i>TRP-1</i>), and tyrosinase-related protein-2 (<i>TRP-2</i>).Result: Melanin production was effectively downregulated by TME treatment in B16F10 cells, showing a dose-dependent reduction in the expression of tyrosinase and <i>TRP-1</i> at the mRNA level.Conclusion: The results suggest the potential utilization of thinned immature apple mango as a skin-beautifying food material with a whitening function.

Nutritional Composition, Mineral Profiling, In Vitro Antioxidant, Antibacterial and Enzyme Inhibitory Properties of Selected Indian Guava Cultivars Leaf Extract.

Psidium guajava L. is a small evergreen tree known for its magnificent medicinal and nutritional value. This study aimed to evaluate the nutritional profile and in vitro pharmacological potentialities of the different leaf extracts of four cultivars of Psidium guajava namely Surka chitti, Allahabad safeda, Karela, and Lucknow-49. The standard procedures of the Association of Official Analytical Chemists (AOAC) were followed to carry out the nutritional analysis and all of the cultivars recorded the presence of elements at a nominal range. The highest presence of phenols (125.77 mg GAE/g) and flavonoids (92.38 mg QE/g) in the methanolic leaf extract of the Karela cultivar was recorded. A wide range of minerals such as sodium, phosphorus, magnesium, zinc, and boron were recorded with a higher percentage in the Karela cultivar of Psidium guajava. In the enzyme inhibitory assays, Allahabad safeda showed potential inhibition with an IC50 of 113.31 ± 1.07, 98.2 ± 0.66 and 95.73 ± 0.39 μg/mL in α-amylase, α-glucosidase, and tyrosinase inhibition assays, respectively. The strong antioxidant effect was established by Lucknow-49 (IC50 of 74.43 ± 1.86 μg/mL) and Allahabad safeda (IC50 of 78.93 ± 0.46 μg/mL) for ABTS and DPPH assays, respectively. The ethyl acetate and methanolic leaf extracts of the Allahabad safeda cultivar showed better inhibition against Pseudomonas aeruginosa with an MIC of 14.84 and 28.69 µg/mL, respectively. A decent mean zone of inhibition was recorded in methanolic leaf extract that ranged from 21-25 mm in diameter against the tested bacterial strains (Proteus vulgaris, Bacillus subtilis, and P. aeruginosa). This is the first scientific report on the comparative and comprehensive analysis of indigenous guava cultivars to evidently shortlist the elite cultivars with enriched dietary nutrition and biological activities.

Changes in the Biological Activities of Gracilaria verrucosa Extracted Using Different Extraction Solvents

This study investigated the antioxidant, antiaging, and antibacterial properties of Gracilaria verrucosa (GV) based on 95% methanol (GVM), ethanol (GVE), and hot water (GVW) extractions. Antioxidant activity assays revealed the total polyphenol and flavonoid contents were highest in GVM and GVE. The 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2′-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activities were highest in GVE and GVM. Furthermore, GVE exhibited the highest ferric-reducing antioxidant power (FRAP) value. In comparison, superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were highest in GVM. Collectively, GVE and GVM had stronger antioxidant activities than GVW. Additionally, collagenase, elastase, and tyrosinase inhibition assays showed that GVM exhibited the strongest anti-wrinkle and skin-whitening activities. Liquid chromatography–tandem mass spectrometer (LC–MS/MS) revealed that GVW had the highest 4-hydroxy benzoic acid content, whereas GVE had the highest naringenin and naringin contents. Additionally, GVE exhibited the strongest antimicrobial activity against six foodborne bacteria, with minimum inhibitory and bactericidal concentrations of 0.06–0.3 and 0.1–0.5 μg/μL. Correlation analysis of the GV extracts indicated a strong positive relationship between TPC and ABTS, SOD, and CAT activities (r = 0.760–0.982, p = 0–0.018). Overall, GVE and GVM can be applied to the development of functional agents across diverse industries.

Evaluation of antioxidant and anti-tyrosinase activities of surfactant and alcohol extracted Combretum Indicum leaves

Combretum Indicum (CI), which contains numerous bioactive compounds, has been used in traditional medicine for a variety of reasons, including the treatment of skin conditions. This study investigates the antioxidant and anti-tyrosinase activities of CI leaves extracted using different surfactants (Triton X-100 and Vitamin E TPGS) at concentrations of 1%, 2%, and 3%, as well as various alcohol solvents (acetone, methanol, and ethanol) at concentrations of 50%, 70%, and 90%. The antioxidant activity of the extracts has been evaluated using Total Phenolic Content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH), while the anti-tyrosinase activity was assessed through a mushroom tyrosinase inhibition assay. Prior to analysis, CI leaves had been macerated, extracted, and freeze-dried. The research established that ethanol at a concentration of 50% is the optimum solvent to extract CI leaves, as it demonstrated good antioxidant and anti-tyrosinase action with a high percentage of yield and total phenolic content. As a result, the outcomes of this study contribute to a better understanding of the potential applications of CI leaf extract in cosmetics, notably in the treatment of oxidative stress and hyperpigmentation. Further study and development in this field could lead to the creation of effective and natural cosmetic products produced from CI leaves that have antioxidant and anti-tyrosinase effects.

Bioactivity profiles of six baobab fruit pulp powders via planar chromatography hyphenated with effect-directed analysis

Baobab (Adansonia digitata) fruit pulp has a high nutrient content and has been traditionally used for medicinal purposes (e.g., as an anti-inflammatory and antioxidant agent) that may help protect against chronic diseases. Six different baobab fruit pulp powders were investigated using three different extractants and analyzed by high-performance thin-layer chromatography (HPTLC) hyphenated with antibacterial bioassays and enzyme inhibition assays. The developed non-target effect-directed screening was performed after extraction with pentyl acetate – ethanol 1:1 (V/V) on the HPTLC plate silica gel 60 using toluene – ethyl acetate – methanol 6:3:1 (V/V/V) as mobile phase system and derivatization via the anisaldehyde sulfuric acid reagent for detection. The physico-chemical profiles of the six baobab fruit pulp powder extracts were comparable, although the intensity of some zones was moderately different. The following effect-directed profiling via tyrosinase, α-glucosidase, and acetylcholinesterase inhibition assays as well as antibacterial Aliivibrio fischeri and Bacillus subtilis bioassays revealed one prominent multipotent bioactive compound zone in common, more or less active in all five studied (bio)assays. Via the recording of high-resolution mass spectra, this compound zone was tentatively assigned to coeluting saturated (palmitic acid 16:0 and stearic acid 18:0), monounsaturated (oleic acid 18:1), and polyunsaturated (linoleic acid 18:2 and linolenic acid 18:3) fatty acids. This finding was confirmed by other studies, which already proved individual activities of fatty acids. The first (bio)activity profiling of baobab fruit pulp powders via HPTLC-effect-directed analysis revealed that the baobab fruit could be considered as a functional food, however, further research is needed to study the impact on health and the influences on the bioactivity arising from different climates, years and soils or regions.

Chemical composition and biological propensities of Wikstroemia indica (L.) C. A. Mey (Tie Bush)

Wikstroemia indica (L.) C. A. Mey. (Thymelaceae) is well documented for use in traditional medicine, but scientific studies on this plant species are lacking. Hence, its phytochemical and pharmacological properties were investigated using different methods. The total phenolic (66.00 ± 0.44 mg GAE/g), flavonoid (69.96 ± 0.32 mg RE/g), phenolic acid (32.59 ± 1.29 mg CE/g) and flavonol (4.46 ± 0.07 mg CAE/g) content of the methanolic extract (ME) was highest when compared to the ethyl acetate extract (EAE) and aqueous extract (AE) respectively. Altogether, 31 compounds were identified by HPLC (High Performance Liquid Chromatography) method. The DPPH (2,2-diphenylpicrylhydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), FRAP (Ferric reducing antioxidant power assay), assays demonstrated that the ME had the highest antioxidant potential with recorded values of 188.38 ± 0.22, 421.31 ± 14.54, 397.10 ± 2.68 and 651.19 ± 16.90 mg TE/g respectively. Regarding the acetylcholinesterase, the ME and the EAE were the best inhibitors (3.13 ± 0.11 and 3.11 ± 0.14 mg GALAE/g). Only the EAE was active against the butyrylcholinesterase enzyme with recorded value of 7.05 ± 0.14 mg GALAE/g. The tyrosinase inhibitory assays demonstrated that the extract inhibitory potential was in the following order: ME (117.63 ± 2.53 mg KAE/g) > EAE (112.57 ± 0.85 mg KAE/g) > AE (13.65 ± 0.87 mg KAE/g). The alpha amylase inhibitory potential of the EA and ME were the same (0.68 ± 0.01 mmol ACAE/g) and better than the AE (0.10 ± 0.01 mmol ACAE/g). HT 29 treated with W. indica in aqueous started to exhibit cell cytotoxicity from 500 µg/mL. The IC50 value exhibited at 786.14 µg/mL. W. indica can be developed into extracts to promote general health pending toxicological studies that show the plant is entirely safe for human consumption.

A review on tyrosinase inhibition potential of plant extracts for skin whitening

Fair skin is considered a trait of beauty in many cultures all over the world. Hence, there is an increased demand for skin whitening products. Since synthetic skin whitening products which are available in the market are associated with adverse effects, attention has shifted towards plant extracts with tyrosinase inhibitory potencies, as natural products are safe and effective. This study was conducted as a systematic review of plants with skinwhitening properties using a tyrosinase inhibitory assay. Research articles that were published between the years 2010-2021 were studied for this review article. The review was based on two inclusion criteria and two exclusion criteria. When it comes to inclusion criteria, tyrosinase inhibitory assay was used for extract assessment, and only the English articles were revised. The research papers that lack half maximal inhibitory concentration analysis were rejected, and only plant extracts were considered, while compounds were rejected. From a total of 70 articles that were studied, only 23 were considered relevant. IC50 values of tyrosinase inhibitory assay in different plant extracts were considered, and the details were tabulated. The highest tyrosinase inhibitory potency was recorded from the methanol extract of Quercus infectoria galls with an IC50 value of 3.34 μg/ml, while the second highest tyrosinase inhibitory potency was recorded from the methanol extract of Terminalia chebula fruit with an IC50 value of 3.87 μg/ml. The families Balanophoraceae and Caprifoliaceae showed high tyrosinase inhibitory potencies, while the families Sapotaceae, Clusiaceae, Fabaceae, Solanaceae, and Malvaceae showed moderate tyrosinase inhibitory potencies. Therefore, it can be concluded that the plants from the above-mentioned families possess active tyrosinase inhibition properties. It was also observed that even when comparing the same plant part of the same species when the polarity of the solvent used for extract preparation is low that the IC50 value tends to be high.