Ethyl Acetate Sub-extracts Research Articles

Bioactive phenolic contents of Scorzonera ketzkhowelii Sosn. ex Grossh. (Asteraceae) with comprehensive in vitro and in silico studies

This study explores the antioxidant, anti-inflammatory, and anticholinesterase properties of extracts from the natural plant Scorzonera ketzkhowelii for the first time. Additionally, it focuses on isolating phenolic compounds from the ethyl acetate sub-extract, elucidating their structures, and investigating their in-silico bioactivities. Twelve phenolic compounds were isolated and characterized from the ethyl acetate sub-extracts, including hydrangenol (1), 4-hydroxybenzaldehyde (2), luteolin (3), esculin (4), 3-O-caffeoylquinic acid ethyl ester (5), 3-O-caffeoylquinic acid methyl ester (6), kaempferol 3-O-β-glucopyranoside (7), quercetin 3-O-α-arabinopyranoside (8), 3,5-di-O-caffeoylquinic acid ethyl ester (9), thunberginol F 7-O-β-D-glucopyranoside (10), hydrangeic acid 4′-O-β-D-glucopyranoside (11), and 3-O-caffeoylquinic acid (12). The ethyl acetate sub-extracts from both aerial and subaerial parts demonstrated exceptional radical scavenging activity. Moreover, all fractions exhibited potent inhibition against COX-I and COX-II enzymes, with notable inhibitory effects observed in the ethyl acetate and dichloromethane sub-extracts against AChE. Additionally, the inhibitory effects of these compounds were assessed against various biological targets, including TNFα, COX-I, COX-II, human CYP450, and hAChE, through molecular docking studies. According to the molecular docking and dynamics studies, compound 9 emerged as particularly noteworthy across all complexes, exhibiting stable binding modes and promising interactions with key residues involved in inhibition.

QUANTITATIVE HPLC ANALYSIS AND ISOLATION OF TILIROSIDE FROM Alcea biennis Winterl AND DETERMINATION OF TOTAL FLAVONOID CONTENT AND BIOLOGICAL ACTIVITIES

Natural products are being investigated to obtain potential agents that could be used to prevent and ameliorate obesity and oxidative stress, which are two important factors that cause many metabolic disorders in the body. This study aimed to isolate and quantify the major compounds, to determine total flavonoid content, and to evaluate biological activities (antioxidant and pancreatic lipase (PL) inhibitory activity) of the methanol extract and the chloroform, ethyl acetate and the remaining aqueous subextracts of Alcea biennis Winterl. The major compound isolated from the ethyl acetate subextract was determined as tiliroside (kaempferol 3-O-β-(6″-O-trans-p-coumaroyl-glucopyranoside) using 1D-NMR and 2D-NMR spectral methods. The quantification of tiliroside in the extracts was specified by the newly validated high-performance liquid chromatography (HPLC) method. Ferric-reducing antioxidant power (FRAP) assay was performed to determine the antioxidant activity and the total flavonoid content was determined. The ethyl acetate subextract was found to have the highest tiliroside (75.4263 mg/g) and total flavonoid content (189 mg QE/g) and showed the highest FRAP value (259 ± 5.1316 µM TE/g). The methanol extract had a higher PL inhibitory activity (IC50 = 100.891 ± 5.160 µg/mL) compared to the other extracts. Tiliroside exhibited higher activity (IC50 = 86.203 ± 6.323 µg/mL) than the extracts. It has been demonstrated that A. biennis may be a promising plant for treatment of obesity, and further studies should be conducted to evaluate it as a therapeutic agent.

Qualitative and quantitative phytochemicals of essential oils and extracts of Thymbra spicata subsp. spicata L. as a spice for diabetes mellitus

AbstractThe aim of this paper was to evaluate the antidiabetic and antioxidant activities of methanolic extracts, n‐hexane, dichloromethane, ethyl acetate, butanol, aqueous subextracts and essential oils of flowers, roots, leaves and aerial parts of Thymbra spicata subsp. spicata, which has been utilized in the public medicine systems of Turkey, Greece, Egypt and Rome for the treatment of asthma and bronchitis, as well as for flavour and aroma in the food industry and protection. Quantitative determination of secondary metabolites in the most effective samples of the plant was also analysed by LC–MS/MS. Moreover, the chemical composition of essential oils of different parts of the plant was analysed via GC‐FID and GC/MS. The main constituents in the flower, leaf and aerial part were found to be carvacrol (75.6%), γ‐terpinene (10.5%), carvacrol (73.3%), γ‐terpinene (9.5%), p‐cymene (8.6%), carvacrol (76.1.8%) and p‐cymene (7.3%), respectively. Quinic acid, caffeic acid, vanillic acid, naringin, hesperidin and rosmarinic acid were measured in four ethyl acetate subextracts, and rosmarinic acid was found to have the highest amount in the flower subextract with a value of 48095.1083 ng/mL. The ethyl acetate extract of flowers showed the best activity with a 326 ± 12 μg/mL IC50 value, while the standard acarbose IC50 value was 4143 ± 243 μg/mL. It was determined that the leaf ethyl acetate extract, in particular, had a very high % inhibition value on ABTS·+ (99.137 ± 0.011% inhibition) and DPPH• (41.068 ± 0.031% inhibition). It is thought that the plant, which has been used as a spice in the kitchen for centuries by the public, can be safely used due to its high antidiabetic and antioxidant effects.

Evaluation of the Chemical Composition, Antioxidant and Antidiabetic Activity of Rhaponticoides iconiensis Flowers: Effects on Key Enzymes Linked to Type 2 Diabetes In Vitro, In Silico and on Alloxan-Induced Diabetic Rats In Vivo.

Diabetes mellitus (DM) is one of the globally worst killer diseases. In this study, the in vitro and in vivo antidiabetic activity and antioxidant capacity were determined and the phytochemical analyses were carried out on flower extract and sub-extracts of Rhaponticoides iconiensis. The in vitro antidiabetic activity was tested with α-amylase and α-glucosidase enzyme inhibition methods and an in vivo OGTT test in healthy and alloxan-induced rats. Although, the antioxidant activity was investigated with DPPH●, ABTS●+ and FRAP tests, the phytochemical composition analysis was carried out by LC-MS/MS. The highest α-glucosidase and α-amylase activity even from positive control acarbose were found in the ethyl acetate sub-extract of R. iconiensis (IC50 = 11.737 ± 0.823 µg/mL and 84.247 ± 0.721 µg/mL, respectively). This sub-extract also was active according to the results of in vivo tests. Moreover, the highest antioxidant activity on DPPH● (IC50 = 0.126 ± 0.002 mg/mL), FRAP (at a concentration of 1 mg/mL equivalent to 3112.052 ± 2.023 mmol Fe2+) and ABTS+● (at a concentration of 0.5 mg/mL equivalent to 0.608 ± 0.005 µM Trolox) tests. In addition, LC-MS/MS analyses of the active sub-extract revealed mainly the presence of patuletin, patuletin 3,7-diglucoside, naringin and 3,4-dicaffeoylquinic acid detected in the active sub-extract. In silico molecular docking and dynamics simulations studies were performed on these compounds with α-amylase and α-glucosidase enzymes for protein-ligand interactions and stability.

Wound healing acceleration and anti-inflammatory potential of Prunella vulgaris L.: From conventional use to preclinical scientific verification

Ethnopharmacological relevanceThe genus Prunella L. (Lamiaceae) is represented by nine species in the world and four species in Turkey. The infusion prepared from the aerial parts of Prunella vulgaris L. is used internally for abdominal pain and as an expectorant, the decoction prepared from all parts is used internally or externally as a wound healing. Aim of the studyThis study aims to investigate the wound healing potential of Prunella vulgaris L. on the scientific platform. Material and methodsThe aerial parts of the plant were extracted with 80% methanol. The resulting aqueous methanol extract was partitioned with n-hexane and ethyl acetate, and sub-extracts were obtained. The wound healing effects of the methanol extract and sub-extracts were studied in mice and rats using linear incision and circular excision wound models, and the anti-inflammatory effect was investigated using acetic acid-induced capillary permeability test. Isolation studies were performed using the ethyl acetate sub-extract, which exhibited the highest activity. ResultsUsing various chromatographic methods, 6 compounds were isolated from the ethyl acetate sub-extract. The structures of the compounds were identified as methyl arginolate, ursolic acid, chlorogenic acid, rosmarinic acid, methyl 3-epimaclinate, and ethyl rosmarinate by spectroscopic techniques (UV, IR, 13C-NMR, 1H-NMR, 2D-NMR, MS). The wound healing mechanisms of the pure compounds were investigated by performing assays to inhibit the enzymes hyaluronidase, collagenase, and elastase. Ursolic acid, chlorogenic acid, and rosmarinic acid were found to be responsible for the anti-inflammatory and wound healing effects. ConclusionThe experimental study revealed that Prunella vulgaris showed significant wound healing and anti-inflammatory activities.

Investigation of Antidiabetic Effect of Pistacia atlantica Leaves by Activity-Guided Fractionation and Phytochemical Content Analysis by LC-QTOF-MS.

In this study, the antidiabetic, antiobesity, antioxidant, and antihyperlipidemic effects potential of Pistacia atlantica Desf. leaves were evaluated by in vitro methods. The effects of the leaves of the plant on pancreatic lipase, pancreatic cholesterol esterase, and PTP1B enzymes were investigated for the first time and it was observed that leaf methanol extract (IC50: 123.67 ± 0.40 μg/ml) and n-hexane sub-extract (IC50: 61.03 ± 0.11 μg/ml) had much stronger effects on pancreatic cholesterol esterase enzyme than simvastatin (IC50: 142.30 ± 5.67 μg/ml). The methanolic extract of P. atlantica leaves exerted strong inhibitory effect on the enzymes (α-amylase and α-glucosidase) effective on carbohydrate digestion. It was thought that the methanol extract could provide significant benefits against oxidative stress in diabetes mellitus since it showed antioxidant activities (DPPH radical scavenging activity and reducing power) as strong as reference compounds (ascorbic acid and quercetin). Qualitative and quantitative analyzes of rutin (0.328 ± 0.000 g/100 g dry extract), methyl gallate (5.245 ± 0.014 g/100 g dry extract), quercetin-3-O-glucoside (0.231 ± 0.000 g/100 g dry extract), and gallic acid (0.528 ± 0.127 g/100 g dry extract) in methanol extract were performed by RP-HPLC. The phytochemical content of the active sub-fraction obtained from the leaf methanol extract by activity-guided fractionation and column chromatography studies was characterized by LC-QTOF-MS. The presence of trigalloylglucose, digalloylglucose, and methyl gallate in the G6 coded sub-fraction obtained by chromatographic techniques from the ethyl acetate sub-extract, which has the highest inhibitory effect on α-amylase and α-glucosidase enzymes, was determined by LC-QTOF-MS. In addition to the G5 coded subfraction, a strong α-glucosidase enzyme inhibitory activity was also observed in the G6 coded sub-fraction, and methyl gallate, methyl digallate, 2″-O-galloyl-quercetin-3-O-hexoside, and myricetin-3-O-hexoside were identified in this sub-fraction. This study displayed that the methanol extract of P. atlantica leaves could be a potential source for bioactive compounds with antidiabetic effects by showing inhibitory effects on enzymes involved in carbohydrate digestion.

Primary investigating chemical constituents of bioactive extract from Centrostachys aquatica (R.Br.) Wall. ex Moq.-Tand.

This study is aimed to screen the biological activities and chemical composition to find evidences for potential medicinal applications of Centrostachys aquatica in the Mekong Delta. Crude methanol extract and subextracts in n-hexane, ethyl acetate, and acetone from Centrostachys aquatica were tested bioactivities. The methanol extract, n-hexane and ethyl acetate subextracts exhibited antimicrobial activity with corresponding MIC values of 200, 100 and 200 µg/mL, respectively. The ethyl acetate subextract was inhibited cytotoxicity against cancer cell line LU-1 with IC50 of 27.66 µg/mL. None of the extracts showed antioxidant ability. Three known secondary metabolites including oleanolic acid (1), 20(E)-hydroxy-b-ecdysone (2), and b-spinasterol (3) were isolated for the first time from the bioactive (ethyl acetate) subextract of Centrostachys aquatica. Their structures were elucidated by modern spectra as MS, NMR and comparison with published data.

Phytochemical composition and cytotoxic activity of four Cousinia Species against human hepatocellular carcinoma (HepG2) cell line

BackgroundCousinia Cass. is one of the most diverse genus of Asteraceae family. According to previous studies some Cousinia species showed significant cytotoxic activity. PurposeIn this study, we aimed to investigate the cytotoxic activity and phytochemical profile of four Cousinia species (C.davisiana Hub.-Mor., C.foliosa Boiss. & Balansa, C.ramosissima DC, C.stenocephala Boiss). MethodsThe cytotoxic activity was investigated with SRB method against HepG2 (human hepatocellular carcinoma) cell line. The quantitative and qualitative determination of compounds were carried out by LC-MS/MS. ResultsIn a result, C. davisiana methanol extract (CD) and ethyl acetate sub-extract (CDE) showed more cytotoxic activity with 150 and 89 µg/ml IC50 values, respectively. The mass spectrums revealed the presence of 15 compounds in CD methanol extract and 9 compounds in active CDE sub-extract. According to quantitative analyses the highest contents of all compounds were detected in CD extract. ConclusionMoreover, this study on inhibitory activity of CD extract and CDE sub-extract suggests detailed investigation for cytotoxic activity.

Pharmacognostical Studies on Acer campestre L. subsp. campestre

This study on Acer campestre L. subsp. campestre, used traditionally in treatments of various inflammation disorders, especially hemorrhoids and rheumatism, aimed to determine the total phenolic contents, the antioxidant and antimicrobial potentials, and the chemical composition profile of the extracts and subextracts from maple syrup and Acer campestre L. subsp. campestre leaves and twigs. The antioxidant activities of maple syrup extracts and subextracts were examined by 2,2-diphenyl-1-picryl-hydrazyl (DPPH), and the total phenolic contents of all samples were determined using the Folin-Ciocalteu reagent (FCR) method. Also, they were tested for their antimicrobial activities by microbroth dilution technique. Catechic tannin, saponins and flavonoids are determined in its leaves and twigs by preliminary qualitative phytochemical analysis. The alcoholic extracts obtained by 48-hour maceration (91.2%), ethyl acetate subextract of alcohol extracts obtained by 24-hour maceration (91.1%) and alcohol extracts obtained by 24-hour maceration (88.8%) exhibited higher radical scavenging activity than other samples, while the decoction and infusion had moderate activities. Beside of this, it was found that the syrup and its subextracts have more total phenolic contents than other extracts. The alcohol extracts obtained by 24-hour maceration and by 48-hour maceration exhibited higher activity against Candida albicans (78 μg/mL and 156 μg/mL, respectively). Only the alcohol extract obtained by 48-hour maceration and ethyl acetate subextract of syrup showed an activity against Escherichia coli, while all samples except butanol subextract of syrup have an antibacterial activity against Pseudomonas aeruginosa.

In vitro antioxidant capacity and phytochemical characterization of Eryngium kotschyi Boiss.

Context: Eryngium kotschyi is one of the species of Eryngium genus and was endemic to Turkey. It was known, that traditionally uses of this plant in the South-Western part of Turkey for the treatment of various diseases. Aims: To evaluate the antioxidant capacities of methanol extract and ethyl acetate, n-butanol and water sub-extracts as well as to determine the phytochemical composition and to quantify the major antioxidant compounds in the active sub-extract. Methods: Besides the total phenolic compounds and total flavonoid compounds, the antioxidant capacity of E. kotschyi was evaluated by DPPH●, ABTS+● and FRAP methods and qualitative and quantitative determination of phytochemical constituents in active sub-extract by LC-MS/MS. Results: The highest total phenolic (173.710 ± 1.088 mg gallic acid equivalent/gextract) and total flavonoid content (86.978 ± 0.650 mg catechin equivalent/gextract) was found in ethyl acetate sub-extract of E. kotschyi (EKE) and this sub-extract showed the highest antioxidant capacity on DPPH● (IC50 = 0.264 ± 0.040 mg/mL), ABTS+● (at a concentration of 0.125 mg/mL equivalent to 0.497 µM Trolox) and FRAP (at a concentration of 1 mg/mL equivalent to 1476 ± 5.292 mmol Fe2+) tests. Preliminary examination of the mass spectrums revealed the presence of 24 phytochemical compounds in this sub-extract and 7 of them was quantified. According to quantitative analyses the main compounds of EKE sub-extract were rosmarinic acid (490.820 ± 0.703 µg/mgextract), chlorogenic acid (80.405 ± 0.170 µg/mgextract), isorhamnetin 3-O-rutinoside (72.280 ± 0.33 µg/mgextract), rutin (63.020 ± 0.052 µg/mgextract) and caffeic acid (55.153 ± 0.523 µg/mgextract). Conclusions: The data suggest that EKE possess utilizable antioxidant properties in vitro. The antioxidant capacity of this sub-extract could be due to high content of phenolic and flavonoid contents.

Inhibitory activity of Podospermum canum and its active components on collagenase, elastase and hyaluronidase enzymes

Present study is aimed to investigate in vitro inhibitory effects of the extract prepared from the aerial parts of Podospermum canum (syn: Scorzonera cana var. jacquiniana) (Asteraceae) on hyaluronidase, collagenase, and elastase enzymes using a bioassay-guided fractionation. Inhibitory effects of the extract, sub-extracts, fractions obtained by column chromatography, and isolated compounds on collagenase, elastase, and hyaluronidase were performed by using in vitro enzyme inhibitory assays based on spectrophotometric evaluation. The methanolic extract obtained from P. canum exhibited strong inhibitory activities on elastase and collagenase while the insignificant activity was observed on hyaluronidase. Through bioactivity-guided fractionation, the ethyl acetate and remaining water sub-extracts obtained from the methanolic extract displayed significant inhibitory activities on collagenase and elastase, while petroleum ether and chloroform extracts did not show any inhibitory activity. Eleven known compounds: arbutin, 6́-O-caffeoylarbutin, cichoriin, 3,5-dicaffeoylquinic acid methyl ester, apigenin 7-O-β-glucoside, luteolin 7-O-β-glucoside, apigenin 7-O-β-rutinoside, isoorientin, orientin, vitexin, procatechuic acid, and new compound 4-hydroxy-benzoic acid 4-(6-O-α-rhamnopyranosyl-β-glucopyranosyl) benzyl ester have been obtained from ethyl acetate sub-extract. Results of the present study have revealed that apigenin 7-O-β-glucoside, luteolin 7-O-β-glucoside, apigenin 7-O-β-rutinoside, and isoorientin showed potent enzyme inhibitory activities. However, methanolic extract of P. canum displayed a greater inhibitory activity than fractions and isolated compounds both on collagenase and elastase.

Activity evaluation on Ribes species, traditionally used to speed up healing of wounds: With special focus on Ribes nigrum

Ethnopharmacological relevanceRibes species are usually evergreen shrubs, represented by eight species in Turkey. Although they are known for their fruits with commercial importance, their leaves have been used as folk remedy in various areas in Turkey by rural population owing to their wound healing potential. Aim of the studyIn the present study we aimed to assess the wound healing activity of the leaves of Ribes species growing in Turkey, namely, Ribes alpinum L., R. anatolica Behçet, R. petraeum Wulfen, R. multiflorum Kit. ex Romer & Schultes, R. nigrum L., R. orientale Desf., R. rubrum L., R. uva-crispa L. Materials and methodsWounds were surgically induced on the dorsal parts of the rats and mice. Prepared herbal ointments were topically applied onto the wounds once daily. The effects of the extracts were evaluated by measuring the breaking strength and percentage of reduction in wounded area by comparing the results with the registered reference ointment, FITO Krem®. Histopathological and antioxidant assays were also conducted. Since, R. nigrum was determined to be the most active species, we further investigated the wound healing potential of the subextracts of the methanol extract of R. nigrum leaves. ResultsR. nigrum and R. multiflorum extracts significantly increased wound breaking strength. Significant reduction in the areas was determined for the wounded tissues treated with the ointments of R. nigrum and R. multiflorum extracts. Oxidative Stress Index was found to be lowest for R. orientale, R. nigrum and R. multiflorum. Among the subextracts of R. nigrum, ethyl acetate subextract was found to have promising effect. ConclusionsMethanol extracts of leaves of R. nigrum and R. multiflorum demonstrated significant wound healing effect. We can suggest that ethyl acetate subextract of R. nigrum may be a potential candidate to be used for the development of a wound healing agent.

Phytochemical and Biological Profile of Moricandia arvensis (L.) DC.: An Inhibitor of Pancreatic Lipase.

Pancreatic lipase, a key enzyme for lipid absorption, is one of the most important targets for the treatment of obesity, while natural compounds have recently attracted much interest as potential inhibitors of this enzyme. Here, in an attempt to find new effective agents, the methanolic extract from Moricandia arvensis (L.) DC. and its sub-extracts were investigated for their potential inhibitory activity. The ability to inhibit pancreatic lipase was verified through the in vitro evaluation of the prevention of p-nitrophenyl caprylate hydrolysis. The antioxidant activity was also verified by means of DPPH and β-carotene bleaching tests. Compositional profiling revealed that flavonoid glycosides were the main specialized metabolites present in the methanolic extract from the aerial parts of the plant with kaempferol and quercetin representing the two O-glycosylated aglycones. Kaempferol-3-O-β-(2″-O-glucosyl)-rutinoside and kaempferol-3-O-a-arabinosyl-7-O-rhamnoside were the most abundant flavonols. The crude methanolic extract and the dichloromethane and ethyl acetate sub-extracts showed a strong lipase inhibitory activity, with IC50 values of 2.06 ± 0.02, 1.52 ± 0.02 and 1.31 ± 0.02 mg/mL, respectively. The best capacity to scavenge DPPH radical was detected for the ethyl acetate sub-extract (IC50 = 171.9 ± 1.0 µg/mL), which was also effective in protecting linoleic acid from peroxidation (IC50 = 35.69 ± 2.30 µg/mL). Obtained results support the hypothesis that M. arvensis can be a source of bioactive phytochemicals for the pharmacological inhibition of dietary lipids absorption.

α-Glucosidase inhibitory effects of polyphenols from Geranium asphodeloides: Inhibition kinetics and mechanistic insights through in vitro and in silico studies

Some Geranium species have been used to treat diabetes. To evaluate the scientific basis of this ethnopharmacological use, we aimed to isolate potent α-glucosidase inhibitory metabolites of Geranium asphodeloides Burm. through in vitro bioactivity-guided fractionation. All the tested extracts showed high α-glucosidase inhibitory effect compared to acarbose. Among the tested extracts, the ethyl acetate subextract showed the highest activity with an IC50 value of 0.85 ± 0.01 µM. A hydrolysable tannin, 1,2,4-tri-O-galloyl-β-d-glucopyranose (1), and five flavonoid glycosides, kaempferol-3-O-α-rhamnopyranoside (2), kaempferol-3-O-α-arabinofuranoside (3), quercetin-3-O-β-glucopyranoside (4), quercetin-3-O-α-rhamnopyranoside (5), and quercetin-3-O-α-rhamnofuranoside (6), were isolated from the ethyl acetate subextract. Their structures were identified by 1D- and 2D-NMR experiments. 1 exhibited the highest α-glucosidase inhibitory effect, approximately 61 times more potent than positive control, acarbose, with an IC50 value of 0.95 ± 0.07 µM. Also, 2 was more potent than acarbose. An enzyme kinetics analysis revealed that compounds 2, 3 and 4 were competitive, whereas 1 and 6 uncompetitive inhibitors. Molecular docking studies were performed to get insights into inhibition mechanisms of the isolated compounds in the light of the enzyme kinetic studies using various binding sites of the enzyme model.

Anti-hyperglycaemic and antioxidant effects of Bidens tripartita and quantitative analysis on its active principles.

Bidens species are used for their antidiabetic properties traditionally in many countries. Aim of this study is to evaluate hypoglycaemic and antidiabetic activity of Bidens tripartita extract and to identify its active compounds through bioactivity guided isolation technique. Hypoglycaemic effects of B. tripartita extract and its sub-extracts were investigated in normal and glucose-hyperglycaemic rats. Streptozotocin induced diabetic rats were used to examine antidiabetic activity of the extract and its sub-extracts after acute and sub-acute administration. Additionally, in vitro enzyme inhibitory and antioxidant activities were evaluated. HPLC analyses were carried out to determine the active constituents of the extract and its sub-extracts. Through in vivo bioactivity-guided fractionation process, ethyl acetate and n-buthanol sub-extracts were found to have potent antidiabetic activity. In vitro enzyme inhibitory activities of the same sub-extracts were found to be potent. The highest total phenol, flavonoid contents and radical scavenging activity was determined in ethyl acetate sub-extract. According to LC-MS analyses, chlorogenic acid, luteolin and 7-O-glucoside of luteolin (cynaroside) were determined as the main components of the active sub-extracts. According to our results, B. tripartita has potent antidiabetic activity and its active constituents might be beneficial for diabetes and its complications.

Hypericum lanceolatum (Hypericaceae) as a potential source of new anti-malarial agents: a bioassay-guided fractionation of the stem bark

BackgroundMalaria is a major public health threat in Africa, and traditional medicine continues to play a key role in its control especially in rural areas. A bioassay-guided fractionation was carried out in order to evaluate the anti-malarial potential and the safety of the methanol extract of the Hypericum lanceolatum stem bark.MethodsThe anti-plasmodial activity was assayed by the lactate dehydrogenase method (pLDH) against the multidrug-resistant W2mef laboratory strain, and a field isolate (SHF4) of Plasmodium falciparum. Cytotoxicity tests were carried out using the LLC-MK2 monkey kidney epithelial cells.ResultsFive compounds were isolated from the most active and least cytotoxic ethylacetate sub-extract: betulinic acid (HLT1), 2,2',5,6'-tetrahydroxybenzophenone (HLT2), 5-hydroxy-3-methoxyxanthone (HLT3), 3-hydroxy-5-methoxyxanthone (HLT4) and HLT0 (yet to be identified). Three of the tested compounds presented significant anti-plasmodial activities (with 50% inhibitory concentration, IC50 < 5 μM), with 5-hydroxy-3-methoxyxanthone exerting the highest activity, followed by HLT0 and betulinic acid. All the compounds with significant anti-plasmodial activity were non-cytotoxic, except betulinic acid which showed a 50% cytotoxic concentration, CC50 of 25 μg/mL.ConclusionsThese findings justify the use of H. lanceolatum stem bark as anti-malarial by traditional healers of Western Cameroon, and could constitute a good basis for further studies towards development of new drug candidates or phytomedicines for malaria.

Antimicrobial effect of Helichrysum plicatum subsp. plicatum

The objective of the present study was to investigate the in vitro antibacterial activity of the extracts and their fractions obtained from either the flowers or the leaves of Helichrysum plicatum DC. subsp. plicatum (Asteraceae), by studying inhibition of the growth of a dangerous food pathogen, Escherichia coli O157:H7. The antibacterial effects of the ethanol and water extracts of the flowers and leaves were examined first. Subsequently sub-extracts of the flower ethanol extract (FEE), which was found to be the most effective extract, were examined. As a result, the antibacterial effect of FEE was found to be stronger than that of the chloroform and ethyl acetate sub-extracts. This may due to synergistic activity of several components of the ethanol extract of the flowers.