Evaluation of Antioxidant Capacity and Safety Profile of Selected Medicinal Plant Extracts.

Medicinal plants include a wide range of phytochemicals that contribute to their medicinal benefits, particularly in reducing inflammation, oxidative stress, and cellular damage. The aim is to assess the anti-inflammatory, antioxidant potential, and safety of Ferula asafoetida, Hyoscyamus niger, Matricaria chamomilla, and Styrax benzoin. The antioxidant activity was determined using ABTS, DPPH, FRAP, Lipid peroxidation and nitric oxide scavenging tests. The safety was assessed utilising the Hen’s Egg Test – Chorioallantoic Membrane (HET-CAM) assay. FTIR spectroscopy was utilised for functional group evaluation. M. chamomilla showed the highest carbohydrate, protein, and flavonoid content, while H. niger had the highest phenolic content. F. asafoetida exhibited the lowest DPPH IC50 (2.280±0.041 µg/mL), and FRAP values ranged up to 9.10±0.05 mg Trolox equivalent in M. chamomilla. F. asafoetida and M. chamomilla show the lowest IC50 of 156.84±9.99 and 147.178±4.364 mg Trolox equivalent, respectively, indicating their anti-inflammatory activity. All extracts protected DNA from oxidative damage and showed irritation scores below 1 in the HET-CAM assay. In conclusion, plants showed notable anti-inflammatory and antioxidant activity and safety profiles. F. asafoetida was the most effective radical scavenger, whereas M. chamomilla had the highest phytochemical concentration.

Total phenolic and flavonoid contents and antioxidant activity of four Iranian herbs (Lamiaceae) were investigated. The antioxidant activity of methanol extracts of thyme (Thymus daenensis Celak.), Bakhtiari savory (Satureja bachtiarica Bung.), dragonhead (Dracocephalum multicaule Montbr & Auch), and woundwort (Stachys lavandulifolia Vahl.) was evaluated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP), and trolox equivalent antioxidant capacity (TEAC). A comparison of all plant extracts in the DPPH assay indicated that dragonhead and thyme were the most effective free radical scavenging agents. Thyme demonstrated a relatively strong antioxidant activity in both the FRAP and TEAC assays. The total phenolic content of all the extracts ranged from 99 to 208 mg TAE/g extract with thyme exhibiting the highest phenolic content. The flavonoid content of the extracts, which ranged from 10.1 to 22.2 rutin equivalents/g of extract, was highest in dragonhead. A positive correlation was noted between the total phenolic content and antioxidant activity in both the FRAP and TEAC assays, while no significant correlation was observed between the DPPH, TEAC, and FRAP assay and total flavonoid, suggesting that the level of antioxidant activity in these plants varies greatly, but the total phenolic in the plant extracts provided a substantial antioxidant activity. Experimental results indicate that thyme and dragonhead extracts could be an important dietary source of phenolic compounds with high antioxidant capacity.

Solanum anguivi Lam. is an ethnomedicinal plant. Local traditional practitioners believe that it reduces the risk of diabetes and atherosclerosis diseases. The present study was intended to conduct qualitative phytochemical analysis, determine the total flavonoid and phenolic contents, estimate the antioxidant capacity and antibacterial activities of the extracts of the fruits of this plant. The antioxidant activity was determined by analyzing the radical scavenging activity (RSA) using 2,2-diphenyl-1-picryhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. The antibacterial activities were determined by the agar well diffusion method. Qualitative phytochemical screening of the crude extracts obtained from the fruits of the plant indicated the presence of alkaloids, flavonoids, phenols, glycosides, steroids, terpenoids, saponins and tannins. The highest total phenolic and total flavonoid content were obtained in the ethanol extract of the fruits, followed by dichloromethane and n-hexane extract. The total phenolic content (in gallic acid equivalents, GAE) ranged from 113.3 to 202.72 mg GAE/g. The total flavonoid content (in catechin equivalent, CE) varied from 61.72 to 142.64 mg (CE)/g. All fruit extracts of S. anguivi exhibited antioxidant activity as revealed by DPPH and FRAP assays. The DPPH RSA (% inhibition) of the fruit extract varied from 35.11 to 80.13. The total phenolic and Flavonoid contents showed alinear correlation with RSA. Furthermore, all fruit extracts showed antibacterial activity against gram-positive and gram-negative bacteria varying from 12.5 to 16.75 mm. The result showed that the extracts of the plant exerted stronger bactericidal effect on gram-positive bacteria than on gram-negative bacteria. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1993087 .

Medicinal plants have been used for therapeutic purposes and have shown important biological properties. This study aimed to evaluate for the first time the antioxidant activities, total flavonoid, and total phenolic contents of Lavandula mairei Humbert. The ethanol, methanol, ethyl-acetate, and water extracts were used for this purpose. The antioxidant activities were assessed in vitro by free radical scavenging activity against 2,2-diphenyl-1-picrylhydrzyl (DPPH), ferric reducing antioxidant power (FRAP), and total antioxidant capacity (TAC). The total flavonoid and phenolic contents were determined spectrophotometrically with gallic acid and Quercetin as standards. In either Soxhlet or maceration methods, the flavonoids and the total phenolic contents were significantly higher in the methanolic extract (P<0.05) compared to other extracts. The total flavonoid content of L. mairei ranged between 119 and 224.6 mg QE/g DW for Soxhlet extracts and from 111.8 to 148.51 mg QE/g DW for maceration extracts. While the total phenolic content was between 35.12 and 99.37 mg GAE/g DW for Soxhlet extracts and 27.63 to 58.99 mg GAE/g DW for maceration extracts. In either the Soxhlet or maceration method, the highest total antioxidant capacity (TAC) was obtained using the ethanolic extract, while the aqueous extract had the highest antioxidant activity for DPPH and FRAP assays. These results showed that Lavandula mairei Humbert has great potential to be a promising candidate for natural plant sources of antioxidants.

ABSTRACTThe present study reports the antioxidant and anti-proliferative activities of Polygonum minus leaf extracts obtained through sequential extraction using four solvents of varying polarities (i.e. hexane (HX), ethyl acetate (EA), methanol, and water). The antioxidant potential was evaluated by measuring the total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), 2,2′-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical-scavenging, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical-scavenging, superoxide anion and nitric oxide scavenging, ferrous ion-chelating (FIC), and cellular antioxidant activity (CAA) assays. The highest antioxidant potential was generally shown by the methanol extract (PM-MeOH). PM-MeOH exhibited the highest values for TPC (174.00 ± 0.18 mg GAE/g), TFC (53.19 ± 0.71 mg GAE/g), FRAP (1728.33 ± 0.96 µmol Fe2+/g), ABTS (226.25 ± 4.25 µmol TE/g), DPPH (1276.81 ± 7.08 µmol TE/g), and nitric oxide scavenging assays (IC50, 675 ± 32.33 µg/mL). In the CAA assay, PM-MeOH dose-dependently inhibited the peroxyl radical-induced oxidation of 2ʹ,7ʹ-dichlorodihydrofluorescein (DCFH2) to 2ʹ,7ʹ-dichlorofluorescein (DCF) in HCT116 cells, with an EC50 value of 263.92 ± 21.60 µg/mL. Liquid chromatography and mass spectrometry analyses of PM-MeOH suggested the presence of tannins and flavonoids including apigetrin, hyperoside, isoquercetin, astragalin, miquelianin, quercetin, and quercitrin. P. minus hexane (PM-HX) and ethyl acetate (PM-EA) extracts showed selective cytotoxicity towards HCT116 with IC50 values of 40.00 ± 0.83 µg/mL and 43.18 ± 0.67 µg/mL, respectively. Taken together, these results highlight the potential of P. minus as a source of bioactive phytochemicals that may be useful in cancer therapeutics and nutraceutical industry.

Objective. The aim of this work is to study and compare the antioxidant properties and phenolic contents of aqueous leaf extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus Phoenicea, and Tetraclinis articulata from Morocco. Methods. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging ability, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) assays. Also the total phenolic and flavonoids contents of the extracts were determined spectrophotometrically. Results. All the extracts showed interesting antioxidant activities compared to the standard antioxidants (butylated hydroxytoluene (BHT), quercetin, and Trolox). The aqueous extract of Juniperus oxycedrus showed the highest antioxidant activity as measured by DPPH, TEAC, and FRAP assays with IC50 values of 17.91 ± 0.37 μg/mL, 19.80 ± 0.55 μg/mL, and 24.23 ± 0.07 μg/mL, respectively. The strong correlation observed between antioxidant capacities and their total phenolic contents indicated that phenolic compounds were a major contributor to antioxidant properties of these plants extracts. Conclusion. These results suggest that the aqueous extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus phoenicea, and Tetraclinis articulata can constitute a promising new source of natural compounds with antioxidants ability.

To evaluate the total phenolic content and compare the antioxidant activity of various solvent extracts and fractions from the aerial parts of Coronopus didymus through various assays. Total phenolic content was determined using the Folin-Ciocalteu assay and the invitro antioxidant activity of a number of different extracts was investigated in a dose-dependent manner with three different methods: the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and ferric reducing antioxidant power (FRAP) assays. A flavone was isolated from the most active ethanolic extract with high antioxidant activity using size exclusion chromatography. IC50 values were calculated for the DPPH and ABTS methods. The FRAP activity was assessed in terms of μM Fe (II) equivalent. The phenolic content was found to be highest in the ethanol extract (CDA Et; 47.8mM GAE) and the lowest in the dichloromethane extract (CDA DCM; 3.13mM GAE). The ethanol extract showed high radical scavenging activity towards DPPH and ABTS radicals with IC50 values of (7.80×102) and (4.32×102) μg/mL, respectively. The most active ethanol extract had a FRAP value of 1921.7μM Fe (II) equivalent. The isolated flavone F10C (5,7,4'-trihydroxy-3'-methoxy flavone) was far more effective for scavenging free radicals in the DPPH and ABTS assays with IC50 of 43.8 and 0.08μg/mL, than the standard trolox, with IC50 values of 97.5 and 21.1μg/mL, respectively. In addition, the flavone F10C and the standard ascorbic acid had FRAP values of 1621.7 and 16038.0μM Fe (II) equivalents, respectively. The total phenolic content of extracts in decreasing order is ethanol extract (CDA Et)>acetone extract (CDA ACE)>phenolic extract (CDA MW)>n-hexane extract (CDA nHX)> chloroform extract (CDA CHL)>dichloromethane extract (CDA DCM). The ordering of extracts in terms of antioxidant activity from highest to lowest is CDA Et>CDA MW>CDA DCM>CDA CHL>CDA ACE>CDA nHX in DPPH, ABTS and FRAP assays. A significant relationship is found between antioxidant potential and total phenolic content, suggesting that phenolic compounds are the major contributors to the antioxidant activity of C. didymus.

Emilia sonchifolia (L.) D.C. is a medicinal plant from the family Asteraceae known for a wide range of ethnomedicinal uses such as management of inflammatory diseases, pains, cancer, diabetes, cataract, asthma and liver disease. This research was aimed at assessing the antioxidant potential and quantitative determination of phenolic and flavonoid contents of the extract and fractions of Emilia sonchifolia leaves. The leaves of the plant were processed, extracted and partitioned successively and exhaustively with dichloromethane (DCM) and ethyl acetate. Phytochemical screening was carried out on the methanol extract using standard methods. Antioxidant evaluation of the methanol extract and fractions of Emilia sonchifolia leaves was carried out using Ferric Reducing Antioxidant Power (FRAP) assay and 2, 2, diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Quantitative determination of total phenolic content and total flavonoid content was done. The extraction and partitioning yielded the crude extract and respective fractions. The phytochemical screening revealed the presence of tannins, saponins, flavonoids, alkaloids and cardiac glycosides. Antioxidant evaluation of the crude extract and fractions of the plant exhibited significant (p<0.001) antioxidant activity in both assay though not comparable with the standard agent, ascorbic acid. In DPPH assay, the highest percentage inhibition was observed in ethyl acetate fraction (62%) followed by the extract (61%), DCM fraction (55%) and aqueous fractions (54%) at 100 µg/mL. In FRAP assay, the highest reducing power was exhibited by ethyl acetate fraction (0.457 nm) followed by the extract (0.444 nm), DCM fraction (0.441 nm) and aqueous fraction (0.439 nm). Although these activities were significant, they were not comparable to that of the standard drug ascorbic acid (0.914 nm). In total phenolic content assay ethyl acetate fraction had the highest phenolic content (5.804 mg/g), followed by crude extract (2.500 mg/g). The total flavonoid content was observed to be highest in ethyl acetate fraction (10.556 mg/g), followed by crude extract (4.444 mg/g). From this research work it was observed that Emilia sonchifolia leaves have a good antioxidant activity which could be responsible for its wide range of ethnomedicinal activities and this lends scientific credence for the use of this plant in the management of disease conditions.

Zilla spinosa is commonly used in traditional medicine to treat gastrointestinal disorders and diabetes. In this study, aqueous ethanol (AE) and aqueous methanol (AM) extracts from aerial parts and roots of Z. spinosa were investigated. The total phenolic (TPC) and flavonoid (TFC) contents and antioxidant capacities in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, hydrogen peroxide (H2O2), and ferric reducing antioxidant power (FRAP) assays were determined, and the correlations among the results were assessed using Pearson's correlation. The antimicrobial activity was assessed through agar disc diffusion and broth microdilution assays. Phytochemical screening showed that Z. spinosa extracts had alkaloids, glycosides, saponins, triterpenoids, phenols, and flavonoids in different abundances. The aerial part-AE extract contained low TPC (30.17 ± 4.24 mg GAE/g) and TFC (7.40 ± 1.02 mg QE/g) and displayed significant antioxidant capacity in the DPPH (IC50 = 52.17 ± 7.30 μg/mL), H2O2 (91.22 ± 2.60 μg/mL), and FRAP (EC50 = 98.70 ± 2.21 μg/mL) assays. By contrast, the root-AM extract contained high amounts of TPC (87.72 ± 7.75 mg GAE/g) and TFC (25.60 ± 1.57 mg QE/g). It showed significantly high antioxidant activity with IC50 values of 12.33 ± 1.88 μg/mL in the DPPH and 39.37 ± 2.59 μg/mL in the H2O2 assays, as well as reducing power capacity with an EC50 value of 20.82 ± 1.14 μg/mL in the FRAP assay. Both TPC and TFC were exhibited negative correlations (p < 0.01) with the IC50 and EC50 values obtained in the applied antioxidant assays. The aerial part-AM extract showed the highest inhibitory activity against Staphylococcus aureus (26.5 ± 0.20 mm), followed by Shigella flexneri (19.4 ± 0.40 mm) and Proteus mirabilis (17.7 ± 0.49 mm). S. aureus was the most affected microorganism with a minimum inhibitory concentration of 128 μg/mL against the aerial part-AM extract. Interestingly, all evaluated extracts showed potent antifungal activity against Candida albicans. However, aerial part-AM was the most effective, with an inhibition zone of 12.6 ± 0.17 mm. The results concluded that Z. spinosa possesses different phytochemicals displaying significant antioxidant and antimicrobial activities, thus lending credence to its use in traditional medicine.

Canarium odontophyllum, known locally as “Kembayau” or “Dabai”, is a highly seasonal fruit which is popular among local people in Borneo Island. This study was conducted to determine the antioxidant activity, phytochemicals (total phenolic, total flavonoid, total anthocyanin and total carotenoid contents) and acetylcholinesterase inhibitor potential of extracts of the flesh and seed of this fruit. C. odontophyllum was collected in Beaufort, Sabah, Malaysian Borneo and subsequently freeze-dried and extracted using 80% methanol and distilled water. Antioxidant activities were analyzed using DPPH free radical scavenging, ABTS decolourization and FRAP (Ferric reducing / antioxidant power) assays. Anti-Alzheimer’s potential was determined using acetylcholinesterase enzyme inhibition assay. The results showed that the total phenolic and flavonoid contents were higher in the flesh of C. odontophyllum with the values of 11.96 ± 0.05 mg gallic acid equivalent (GAE)/g and 10.11 ± 1.54 mg rutin equivalent (RU)/g, respectively. Total anthocyanin and carotenoid content were also higher in the flesh of the fruit with the values of 12.75 ± 0.28 mg/100g and 2.84 ± 0.11 mg/100g. The flesh of the fruit also showed higher antioxidant activity as assessed using DPPH, ABTS and FRAP assays. However, anti-cholinesterase activity was higher in the seed of C. odontophyllum which showed that possible other phytochemical content (besides phenolic and flavonoid) which might responsible to the observed effects. The same trend of phytochemicals, antioxidant and anti-cholinesterase activity were also observed in the distilled water extract. These findings suggested that C. odontophyllum is not only nutritious but also displayed potential pharmacological properties.

Seventeen natural sweeteners available on the Polish market were screened for total phenolic content, by the Folin-Ciocalteu method, and for antioxidant activity, using the ferric reducing antioxidant power (FRAP) assay and the 2,2′-Azinobis (3-ethylbenzthiazoline-6-sulphonic acid) radical cation decolorization assay (ABTS·+). In addition, we analyzed antibacterial activities against Staphylococcus aureus strains: both those susceptible and those resistant to methicillin (MRSA). The results of the study showed that total phenolic content, antioxidant activity and antibacterial activity differ widely among different samples of sweeteners. Phenolic content, expressed as a gallic acid equivalent, ranged from 0 mg kg−1 in white, refined sugar, xylitol and wheat malt syrup to 11.4 g kg−1 in sugarcane molasses. Antioxidant activity was lowest in refined white sugar, xylitol, brown beet sugar, liquid fructose, and rape honey; it was average in spelt syrup and corn syrup, and highest in sugar cane, beet molasses, date and barley syrups. Despite the great variety of sweeteners, a strong correlation was noted between the concentration of phenolics and antioxidant properties, as determined by the ABTS·+ method (r = 0.97) and the FRAP assay (r = 0.77). The strongest antibacterial activity was observed in sugarcane molasses, which was lethal to S. aureus strains at 2 and 4% concentrations in medium for susceptible and MRSA strains respectively. Other sweeteners kill bacteria in 6–15% solutions, whereas some did not show any antibacterial activities against S. aureus strains, even at 20% concentrations. Due to their high antioxidant and antibacterial activities, some of the tested sweeteners have potential therapeutic value as supporting agents in antibiotic therapy.

Satureja bachtiarica Bunge. belonging to the family Lamiaceae is an important folkloric medicinal plant in Fars province, South western Iran. In this study, essential oil constituents, phenolic content, antioxidant and antibacterial activities from the aerial parts of S. bachtiarica collected from different natural habitats of Fars province were investigated. The essential oil of all samples was extracted by hydro-distillation using Clevenger type apparatus and analyzed using GC and GC-MS. The main chemical constituents were carvacrol (54.95-65.48 %), thymol (12-15.70 %), γ-terpinene (4.55-13.55 %), p-cymene (1.39-5 %), E-caryophyllene (2.22-4.82 %), linalool (2.34-4.09 %) and borneol (1.25-3.64 %). The total phenolic content and the antioxidant activity of methanolic extracts were determined with the Folin-Ciocalteau reagent and by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing antioxidant power (FRAP) assay, respectively. Total phenols varied from 38.38 to 44.55 mg gallic acid equivalents/g dry weight (dw), and IC50 values in the radical scavenging assay ranged from 30.24 to 37.24 mg/mL, while those in the FRAP assay were between 36.45 and 43.24 μM quercetin equivalents/g dw. Results of this study indicated that methanolic extract of S. bachtiarica have high phenolic content and antioxidant activity. The antimicrobial activity of the essential oils was individually evaluated against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Candida albicans using disc diffusion and serial dilution methods. The oils of various geographical and cultivation methods, showed high activity against four medically important pathogens. The results support the traditional usage and also possible use of S. bachtiarica essential oil and extracts in the food, pharmaceutical and cosmetic industries.

Evaluation of antioxidant activity and total phenolics of selected Czech honeys

Antioxidant activities and phytochemical constituents of Antidesma thwaitesianum Müll. Arg. leaf extracts

Citrus has long been regarded as a food and also as a medicinal plant. Fruits of four species of citrus which are commonly available in Malaysia, namely C. hystrix (wild lime), C. aurantifolia (common lime), C. microcarpa (musk lime) and C. sinensis (orange), were chosen to investigate their total phenolic, flavonoid and hesperidine contents. Additionally, the antioxidant activities were also determined by ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity. C. hystrix had the highest flavonoid and total phenolic contents while C. aurantifolia had the highest hesperidine content. The antioxidant activity of C. hystrix was highest determined by FRAP and DPPH assays compared to other citrus species. A strong positive correlation of R2 = 0.9090 between total phenolic content and FRAP values was observed in this investigation. This study indicated that C. hystrix exhibited the highest antioxidant, flavonoid and phenolic content and can be used potentially as a readily accessible source of natural antioxidant.