Phytochemical characterization and in vitro wound healing activity of leaf extracts from Combretum mucronatum Schum. & Thonn.: Oligomeric procyanidins as strong inductors of cellular differentiation

In vivo anthelmintic activity of Combretum mucronatum schumach & Thonn leaf extract against Haemonchus contortus in goats

Parasitic infections with gastrointestinal nematodes are a serious problem for the health and welfare of domestic animals and negatively affect the economics of animal production. Haemonchus contortus is a haematophagous nematode of small ruminants responsible for significant mortality and morbidity. In addition, the widespread resistance to synthetic anthelmintic drugs emphasizes the urgent need of alternative treatment options against haemonchosis. This work aims to investigate the anthelmintic activity of an hydroethanolic Combretum mucronatum leaf extract (CMLE) against Haemonchus contortus in goats. Goats were artificially infected with 3500 third-stage larvae of H. contortus, and 21 days later, treated with CMLE (1000, 500, 250 mg/kg) for 4 consecutive days. Different parameters such as faecal egg count reduction, weight and haematocrit were monitored during the experimental period. The number of eggs per gram of faeces (EPG) was concentration-depended lower and significantly reduced compared to the untreated control (p < 0.0001). The effect of the highest CMLE dose (4 ×1000 mg/kg body weight) was similar to the effect of albendazole (1 ×5 mg/kg of body weight). The ED50 and ED90 values calculated were 189.17 and 392.33 mg/kg body weight respectively. ED50 and ED90 values were time-dependent. Moreover, CMLE improved haematocrit and weight of goats in dose-dependent and time-dependent manner. These results showed that CMLE could be used for haemonchosis treatment in small ruminants.

Influence of fecal fermentation on the anthelmintic activity of proanthocyanidins and ellagitannins against human intestinal nematodes and Caenorhabditis elegans

Some tannin-rich plants such as Combretum mucronatum and Phyllanthus urinaria are widely used in Africa for the control of parasitic nematodes in both humans and livestock. Tannins have been recognized as an alternative source of anthelmintic therapies, and hence, recent studies have focused on both the hydrolyzable and condensed tannins. These groups of compounds, however, have poor oral bioavailability and are metabolized by gut microbiota into lower molecular weight compounds. The role of these metabolites in the anthelmintic activities of tannins has not been explored yet. This study investigated the effects of fecal metabolism on the anthelmintic potential of procyanidin C1 (PC1) and geraniin and the tannin-enriched extracts of C. mucronatum (CML) and P. urinaria (PUH), which contain these compounds, respectively. Metabolites were formed by anaerobic fermentation of the test compounds and extracts in a fresh human fecal suspension for 0 h, 4 h, and 24 h. Lyophilized samples were tested in vitro against hookworm larvae and whipworm (Trichuris trichiura) larvae obtained from naturally infected human populations in Pru West District, Bono East Region, Ghana, and against the wildtype strain of Caenorhabditis elegans (L4). Both extracts and compounds in the undegraded state exhibited concentration-dependent inhibition of the three nematodes. Their activity, however, significantly decreased upon fecal metabolism. Without fermentation, the proanthocyanidin-rich CML extract was lethal against hookworm L3 (LC50 = 343.5 μg/mL, 95% confidence interval (CI) = 267.5-445.4), T. trichiura L1 (LC50 = 230.1 μg/mL, CI = 198.9-271.2), and C. elegans (LC50 = 1468.1 μg/mL, CI = 990.3-1946.5). PUH, from which the ellagitannin geraniin was isolated, exhibited anthelmintic effects in the unfermented form with LC50 of 300.8 μg/mL (CI = 245.1-374.8) against hookworm L3 and LC50 of 331.6 μg/mL (CI = 290.3-382.5) against T. trichiura L1, but it showed no significant activity against C. elegans L4 larvae at the tested concentrations. Similarly, both compounds, procyanidin C1 and geraniin, lost their activity when metabolized in fecal matter. The activity of geraniin at a concentration of 170 μg/mL against C. elegans significantly declined from 30.4% ± 1.8% to 14.5% ± 1.5% when metabolized for 4 h, whereas that of PC1 decreased from 32.4% ± 2.3% to 8.9% ± 0.9% with similar treatment. There was no significant difference between the anthelmintic actions of metabolites from the structurally different tannin groups. The outcome of this study revealed that the intact bulky structure of tannins (hydrolyzable or condensed) may be required for their anthelmintic action. The fermented products from the gut may not directly contribute toward the inhibition of the larvae of soil-transmitted helminths.

Polyphenols, Antioxidants, and Wound Healing of Lecythis pisonis Seed Coats

To better use the Lecythis pisonis Cambess. biomass, this study investigates whether Sapucaia seed coats present wound healing properties. We analyzed the antibacterial, antioxidant, and wound healing-promoting potentials, plus cytotoxicity and stimulation of vascular endothelial growth factor-A. The chemical composition was analyzed by positive ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. A total of 19 compounds were identified, such as proanthocyanidin A1, procyanidins A1, B2, and C1, epigallocatechin, and kaempferol (p-coumaroyl) glycoside. Potent antioxidant strength/index was verified for 2,2-diphenyl-1-picrylhydrazyl radical (IC50 = 0.99 µg/mL) and ferric reducing antioxidant power (IC50 = 1.09 µg/mL). The extract did not present cytotoxicity and promoted significant cell migration and/or proliferation of fibroblasts (p < 0.05). Vascular endothelial growth factor-A was stimulated dose-dependently at 6 µg/mL (167.13 ± 8.30 pg/mL), 12.5 µg/mL (210.3 ± 14.2 pg/mL), and 25 µg/mL (411.6 ± 29.4 pg/mL). Platelet-derived growth factor (PDGF) (0.002 µg/mL) was stimulated at 215.98 pg/mL. Staphylococcus aureus was susceptible to the extract, with a minimum inhibitory concentration of 31.25 µg/mL. The identified compounds benefit the antioxidant activity, promoting hemostasis for the wound healing process, indicating that this extract has the potential for use in dermatological cosmetics.

Development of an Analytical Workflow to Support the Establishment of Monographs in African Pharmacopoeias - Combretum mucronatum Leaves as Example

Herbal medicines are invaluable in African medicine, but quality and safety are not documented in many cases. Besides controlled farming, validated quality control methods are needed to ensure identity, purity, and content. Analytical specifications within modern monographs are needed for consistent batch quality. Combretum mucronatum leaves are widely used in West Africa, but state-of-the-art quality control methods and specifications are non-existent. The aim of the following study was the development of ICH-validated chromatographic protocols for identity, purity, content assay, and analytical specifications for consideration into pharmacopoeial monographs. UPLC-ESI-Q-TOF-MS/MS was used for untargeted phytochemical information on composition. Optimisation of extraction was based on phytochemical profiling. HPTLC was used for differentiation of C. mucronatum from other Combretum species and UPLC for simultaneous determination of 7 marker compounds. C. mucronatum batch analyses (n = 49) investigated the influence of harvest time and geographical origin. Pesticides screening from a 349-compound panel were carried out. 30 compounds, identified by LC-MS, were used for characterization of the plant material. Orietin, isoorientin, vitexin and isovitexin were used as specific marker compounds for qualitative and quantitative HPTLC purposes, while UPLC quantified additionally epicatechin, procyanidins B2 and C1. Influence of harvest time and geographic origin on the content of marker compounds was observed. Differences in the metabolite profiles of C. mucronatum compared to related Combretum species were established for quality control purposes. Contamination with high amoounts of chlorpyrifos, and folpet (sum of folpet and phtalimide, expressed as folpet) were also observed.The study provides analytical protocols, analytical specifications and a drafted monograph for consideration for African pharmacopoeias, and reveals potential challenges in the quality of C. mucronatum.

Procyanidins: From Agro-Industrial Waste to Food as Bioactive Molecules

Procyanidins are an important group of bioactive molecules known for their benefits to human health. These compounds are promising in the treatment of chronic metabolic diseases such as cancer, diabetes, and cardiovascular disease, as they prevent cell damage related to oxidative stress. It is necessary to study effective extraction methods for the recovery of these components. In this review, advances in the recovery of procyanidins from agro-industrial wastes are presented, which are obtained through ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, pressurized fluid extraction and subcritical water extraction. Current trends focus on the extraction of procyanidins from seeds, peels, pomaces, leaves and bark in agro-industrial wastes, which are extracted by ultrasound. Some techniques have been coupled with environmentally friendly techniques. There are few studies focused on the extraction and evaluation of biological activities of procyanidins. The identification and quantification of these compounds are the result of the study of the polyphenolic profile of plant sources. Antioxidant, antibiotic, and anti-inflammatory activity are presented as the biological properties of greatest interest. Agro-industrial wastes can be an economical and easily accessible source for the extraction of procyanidins.

The Modulatory Influence of Plant-Derived Compounds on Human Keratinocyte Function

The plant kingdom is a rich source of secondary metabolites with numerous properties, including the potential to modify keratinocyte biology. Keratinocytes are important epithelial cells that play a protective role against various chemical, physical and biological stimuli, and participate in reactive oxygen scavenging and inflammation and wound healing processes. The epidermal cell response may be modulated by phytochemicals via changes in signal transduction pathways. Plant extracts and single secondary compounds can possess a high antioxidant capacity and may suppress reactive oxygen species release, inhibit pro-apoptotic proteins and apoptosis and activate antioxidant enzymes in keratinocytes. Moreover, selected plant extracts and single compounds also exhibit anti-inflammatory properties and exposure may result in limited production of adhesion molecules, pro-inflammatory cytokines and chemokines in keratinocytes. In addition, plant extracts and single compounds may promote keratinocyte motility and proliferation via the regulation of growth factor production and enhance wound healing. While such plant compounds may modulate keratinocyte functions, further in vitro and in vivo studies are needed on their mechanisms of action, and more specific toxicity and clinical studies are needed to ensure their effectiveness and safety for use on human skin.

In Vitro Gingival Wound Healing Activity of Extracts from Reynoutria japonica Houtt Rhizomes

Rhizomes of Reynoutria japonica Houtt. are a traditional Chinese medicinal herb (Polygoni cuspidati rhizoma, hu zhang) used for treatment of numerous diseases including wound healing support. The aim of this study was to provide evidence for the value of this herbal drug’s traditional use as a gingival healing treatment as well as to obtain the most active extract. In vitro studies were performed using primary human gingival fibroblasts (HGFs) with determination of viability (MTT assay), cell proliferation (the confocal laser scanning microscope (CLSM) was used to visualize histone 3 expression), cell migration (wound healing assay), and evaluation of the expression of collagen type III (immunocytochemical staining) after incubation with extracts from R. japonica rhizomes (25% or 40% ethanol or 60% acetone). In addition to these extracts, commercial dental rinse (containing chlorhexidine digluconate 0.2%) was tested as the gold standard of choice for gum healing in dental practice. The studied extracts were qualitatively and quantitatively characterized using the validated HPLC/DAD/ESI-HR-QTOF-MS method. Total phenols and tannins content were determined using the Folin–Ciocalteu assay. Low concentration of all extracts after 24 h incubation caused significant increase in HGF viability. This effect was most pronounced at a concentration of 50 µg/mL, which was selected for further experiments. All extracts (at 50 µg/mL) stimulated HGF to proliferate, migrate, and increase collagen III synthesis, but with different strength. The highest stimulated proliferation and migration activity was observed after incubation with 25% EtOH, which according to phytochemical analysis may be related to the highest content of resveratrol and an appropriate composition of procyanidins. The 25% EtOH extract from R. japonica rhizomes appears to be a promising gingival wound healing agent worthy of animal and clinical trials.

Phytochemical Analysis, In Vitro Anti-Inflammatory and Antimicrobial Activity of Piliostigma thonningii Leaf Extracts from Benin

The leaves of Piliostigma thonningii are used in traditional medicine in Benin to treat inflammatory skin diseases and infections. So far, pharmacological studies of the anti-inflammatory and anti-infective effects of phytochemically characterized extracts of P. thonningii have been very limited. Therefore, we investigated the in vitro anti-inflammatory and antimicrobial effect of P. thonningii leaf extracts and analyzed the phytochemical composition of extracts of different polarities (water, 50% ethanol, and n-hexane). Quercetin-3-O-rhamnoside was confirmed as the main flavonoid in the polar extracts. GC-MS analysis identified 20 constituents of the aqueous extract and 28 lipophilic compounds of the n-hexane extract by comparison with authentic standards and spectral library data. The aqueous P. thonningii leaf extract inhibited the IL-8 and IL-6 secretion in TNF-α-stimulated HaCaT cells in a concentration-dependent manner with IC50 values of 74 µg/mL for IL-8 and 89 µg/mL for IL-6. However, an inhibitory effect of the identified quercetin-3-O-rhamnoside and its aglycone, quercetin, on the release of IL-8 and IL-6 could not be demonstrated. In the antimicrobial screening, inhibition zones for a 50% EtOH leaf extract of P. thonningii were found for Staphylococcus epidermidis, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. For none of the microbial strains, however, the MIC was below 500 µg/mL, so that the antibacterial activity must be classified as low. As a result, our investigations primarily support the ethnomedical use of P. thonningii leaf extracts in topical inflammatory conditions. Further studies are required to identify the compounds responsible for the in vitro anti-inflammatory effects.

Phytochemical Characterization and In Vitro Anti-Inflammatory, Antioxidant and Antimicrobial Activity of Combretum collinum Fresen Leaves Extracts from Benin

Leaves from Combretum collinum Fresen (Combretaceae) are commonly used for the treatment of inflammatory conditions, wound healing and bacterial infections in traditional West African medicine. This research focuses on the characterization of the phenolic profile and lipophilic compounds of leaves extracts of C. collinum. Studies of the in vitro anti-inflammatory activity were performed in TNFα stimulated HaCaT cells and antibacterial activity was evaluated with agar well diffusion and microdilution assays. Antioxidant activity was determined by DPPH and ABTS assays and compared to standards. The phytochemical studies confirmed myricetin-3-O-rhamnoside and myricetin-3-O-glucoside as major components of the leaves extracts, each contributing significantly to the antioxidant activity of the hydrophilic extracts. GC-MS analysis identified 19 substances that were confirmed by comparison with spectral library data and authentic standards. Combretum collinum aqueous leaves extract decreased pro-inflammatory mediators in TNFα stimulated HaCaT cells. Further investigations showed that myricetin-3-O-rhamnoside has an anti-inflammatory effect on IL-8 secretion. In the antimicrobial screening, the largest inhibition zones were found against S. epidermidis, MRSA and S. aureus. MIC values resulted in 275.0 µg/mL for S. epidermidis and 385.5 µg/mL for MRSA. The in vitro anti-inflammatory, antibacterial and antioxidant activity supports topical use of C. collinum leaves extracts in traditional West African medicine.

Crataegus Extract WS®1442 Stimulates Cardiomyogenesis and Angiogenesis From Stem Cells: A Possible New Pharmacology for Hawthorn?

Extracts from the leaves and flowers of Crataegus spp. (i.e., hawthorn species) have been traditionally used with documented preclinical and clinical activities in cardiovascular medicine. Based on reported positive effects on heart muscle after ischemic injury and the overall cardioprotective profile, the present study addressed potential contributions of Crataegus extracts to cardiopoietic differentiation from stem cells. The quantified Crataegus extract WS^®1442 stimulated cardiomyogenesis from murine and human embryonic stem cells (ESCs). Mechanistically, this effect was found to be induced by promoting differentiation of cardiovascular progenitor cell populations but not by proliferation. Bioassay-guided fractionation, phytochemical and analytical profiling suggested high-molecular weight ingredients as the active principle with at least part of the activity due to oligomeric procyanidines (OPCs) with a degree of polymerization between 3 and 6 (DP3–6). Transcriptome profiling in mESCs suggested two main, plausible mechanisms: These were early, stress-associated cellular events along with the modulation of distinct developmental pathways, including the upregulation of brain-derived neurotrophic factor (BDNF) and retinoic acid as well as the inhibition of transforming growth factor β/bone morphogenetic protein (TGFβ/BMP) and fibroblast growth factor (FGF) signaling. In addition, WS^®1442 stimulated angiogenesis ex vivo in Sca-1⁺ progenitor cells from adult mice hearts. These in vitro data provide evidence for a differentiation promoting activity of WS^®1442 on distinct cardiovascular stem/progenitor cells that could be valuable for therapeutic heart regeneration after myocardial infarction. However, the in vivo relevance of this new pharmacological activity of Crataegus spp. remains to be investigated and active ingredients from bioactive fractions will have to be further characterized.

Discovering Health Benefits of Phytochemicals with Integrated Analysis of the Molecular Network, Chemical Properties and Ethnopharmacological Evidence

Identifying the health benefits of phytochemicals is an essential step in drug and functional food development. While many in vitro screening methods have been developed to identify the health effects of phytochemicals, there is still room for improvement because of high cost and low productivity. Therefore, researchers have alternatively proposed in silico methods, primarily based on three types of approaches; utilizing molecular, chemical or ethnopharmacological information. Although each approach has its own strength in analyzing the characteristics of phytochemicals, previous studies have not considered them all together. Here, we apply an integrated in silico analysis to identify the potential health benefits of phytochemicals based on molecular analysis and chemical properties as well as ethnopharmacological evidence. From the molecular analysis, we found an average of 415.6 health effects for 591 phytochemicals. We further investigated ethnopharmacological evidence of phytochemicals and found that on average 129.1 (31%) of the predicted health effects had ethnopharmacological evidence. Lastly, we investigated chemical properties to confirm whether they are orally bio-available, drug available or effective on certain tissues. The evaluation results indicate that the health effects can be predicted more accurately by cooperatively considering the molecular analysis, chemical properties and ethnopharmacological evidence.

Study of the non-clinical healing activities of the extract and gel of Portulaca pilosa L. in skin wounds in wistar rats: A preliminary study

INTRODUCTION

Portulaca pilosa L., belonging to the family Portulacaceae, is a common herbaceous plant in the Americas and in the Amazon, is popularly known as love-grown and is traditionally used as an aid in the treatment of burns, buds, insect bites and wound healing. This study aims to evaluate the non-clinical topical healing activity of the P. pilosa gel (GPP) and the propyleneglycol extract of P. pilosa (EPP) in Wistar rats.

METHODS

For the healing activity, wistar rats were divided into the following groups: negative control (GVE - vehicle, 150mg/kg), positive control (Fibrinase^®- FIB, 100U/kg), Portulaca pilosa gel 10%, (GPP, 150mg/kg), and propylenglycollic extract of Portulaca pilosa (EPP, 150 mg/kg), which were submitted to a surgical procedure to obtain the wounds, and were treated topically for 7days. After treatment, the treated area was removed and a histopathological analysis was performed.

RESULTS

The EPP when analyzed in HPLC was able to identify the presence of gallic acid. EPP significantly modulated the tissue inflammatory response, presenting low number of inflammatory cells in the histopathological study. Treatment with EPP and GPP significantly stimulated angiogenesis and this response was superior to the fibrinase^® group. Treatment with EPP and GPP significantly stimulated the proliferation of fibroblasts. The groups treated with EPP and GPP presented an organization pattern of the epidermis and dermis better than the control group, with a mild inflammatory process, with fibroblast proliferation and increased formation of collagen fibers.

CONCLUSION

Thus, from the results obtained it can be suggested that the phytochemical marker of the P. pilosa species for healing activity is gallic acid and, together with the macroscopic and microscopic findings triggered by the topical applications of EPP and GPP, it can be concluded that this plant species has topical healing activity, with great potential for use, since this pharmacological action is associated with a possible topical anti-inflammatory activity.

Isolation, characterization and in silico docking studies of synergistic estrogen receptor a anticancer polyphenols from Syzygium alternifolium (Wt.) Walp

Aim:

This study aims to isolate, characterize, and in silico evaluate of anticancer polyphenols from different parts of Syzygium alternifolium.

Materials and Methods:

The polyphenols were isolated by standard protocol and characterized using Fourier-transform infrared (FT-IR), High performance liquid chromatography - Photodiode array detector coupled with Electrospray ionization - mass spectrometry (MS/MS). The compounds were elucidated based on retention time and molecular ions (m/z) either by [M+H]⁺/[M-H]⁻ with the comparison of standard phenols as well as ReSpect software tool. Furthermore, absorption, distribution, metabolism, and excretion (ADME)/toxicity properties of selected phenolic scaffolds were screened using OSIRIS and SwissADME programs, which incorporate toxicity risk assessments, pharmacokinetics, and rule of five principles. Molecular docking studies were carried out for selected toxicity filtered compounds against breast cancer estrogen receptor a (ERa) structure (protein data bank-ID: 1A52) through AutoDock scoring functions by PyRx virtual screening program.

Results:

The obtained results showed two intensive peaks in each polyphenol fraction analyzed with FT-IR, confirms O-H/C-O stretch of the phenolic functional group. A total of 40 compounds were obtained, which categorized as 9 different classes. Among them, flavonol group represents more number of polyphenols. In silico studies suggest seven compounds have the possibility to use as future nontoxic inhibitors. Molecular docking studies with ERa revealed the lead molecules unequivocally interact with Leu³⁴⁶, Glu³⁵³, Leu³⁹¹, Arg³⁹⁴, Gly⁵²¹, Leu⁵²⁵ residues, and Phe⁴⁰⁴ formed atomic π-stacking with dihydrochromen-4-one ring of ligands as like estrodial, which stabilizes the receptor structure and complicated to generate a single mutation for drug resistance.

Conclusion:

Overall, these results significantly proposed that isolated phenolics could be served as potential ER mitigators for breast cancer therapy.

Ethnopharmacology, Chemistry and Biological Properties of Four Malian Medicinal Plants

The ethnopharmacology, chemistry and pharmacology of four Malian medicinal plants, Biophytum umbraculum, Burkea africana, Lannea velutina and Terminalia macroptera are reviewed. These plants are used by traditional healers against numerous ailments: malaria, gastrointestinal diseases, wounds, sexually transmitted diseases, insect bites and snake bites, etc. The scientific evidence for these uses is, however, limited. From the chemical and pharmacological evidence presented here, it seems possible that the use in traditional medicine of these plants may have a rational basis, although more clinical studies are needed.

The Potential of Plant Phenolics in Prevention and Therapy of Skin Disorders

Phenolic compounds constitute a group of secondary metabolites which have important functions in plants. Besides the beneficial effects on the plant host, phenolic metabolites (polyphenols) exhibit a series of biological properties that influence the human in a health-promoting manner. Evidence suggests that people can benefit from plant phenolics obtained either by the diet or through skin application, because they can alleviate symptoms and inhibit the development of various skin disorders. Due to their natural origin and low toxicity, phenolic compounds are a promising tool in eliminating the causes and effects of skin aging, skin diseases, and skin damage, including wounds and burns. Polyphenols also act protectively and help prevent or attenuate the progression of certain skin disorders, both embarrassing minor problems (e.g., wrinkles, acne) or serious, potentially life-threatening diseases such as cancer. This paper reviews the latest reports on the potential therapy of skin disorders through treatment with phenolic compounds, considering mostly a single specific compound or a combination of compounds in a plant extract.

Review: African medicinal plants with wound healing properties

ETHNOPHARMACOLOGICAL RELEVANCE

Wounds of various types including injuries, cuts, pressure, burns, diabetic, gastric and duodenal ulcers continue to have severe socio-economic impact on the cost of health care to patients, family and health care institutions in both developing and developed countries. However, most people in the developing countries, especially Africa, depend on herbal remedies for effective treatment of wounds. Various in vitro and in vivo parameters are used for the evaluation of the functional activity of medicinal plants by using extracts, fractions and isolated compounds. The aim of the review is to identify African medicinal plants with wound healing properties within the last two decades.

MATERIALS AND METHODS

Electronic databases such as PubMed, Scifinder(®) and Google Scholar were used to search and filter for African medicinal plants with wound healing activity. The methods employed in the evaluation of wound healing activity of these African medicinal plants comprise both in vivo and in vitro models. In vivo wound models such as excision, incision, dead space and burn wound model are commonly employed in assessing the rate of wound closure (contraction), tensile strength or breaking strength determination, antioxidant and antimicrobial activities, hydroxyproline content assay and histological investigations including epithelialisation, collagen synthesis, and granulation tissue formation. In in vitro studies, single cell systems are mostly used to study proliferation and differentiation of dermal fibroblasts and keratinocytes by monitoring typical differentiation markers like collagen and keratin.

RESULTS

In this study, 61 plants belonging to 36 families with scientifically demonstrated or reported wound healing properties were reviewed. Various plant parts including leaves, fruits, stem bark and root extracts of the plants are used in the evaluation of plants for wound healing activities.

CONCLUSION

Although, a variety of medicinal plants for wound healing can be found in literature, there is a need for the isolation and characterization of the bioactive compounds responsible for the wound healing properties. Also, cytotoxicity studies should be performed on the promising agents or bioactive fractions or extracts.

Bioassay-Guided Fractionation of a Leaf Extract from Combretum mucronatum with Anthelmintic Activity: Oligomeric Procyanidins as the Active Principle

Combretum mucronatum Schumach. & Thonn. is a medicinal plant widely used in West African traditional medicine for wound healing and the treatment of helminth infections. The present study aimed at a phytochemical characterization of a hydroalcoholic leaf extract of this plant and the identification of the anthelmintic compounds by bioassay-guided fractionation. An EtOH-H₂O (1:1) extract from defatted leaves was partitioned between EtOAc and H₂O. Further fractionation was performed by fast centrifugal partition chromatography, RP18-MPLC and HPLC. Epicatechin (1), oligomeric proanthocyanidins (OPC) 2 to 10 (mainly procyanidins) and flavonoids 11 to 13 were identified as main components of the extract. The hydroalcoholic extract, fractions and purified compounds were tested in vitro for their anthelmintic activity using the model nematode Caenorhabditis elegans. The bioassay-guided fractionation led to the identification of OPCs as the active compounds with a dose-dependent anthelmintic activity ranging from 1 to 1000 μM. Using OPC-clusters with a defined degree of polymerization (DP) revealed that a DP ≥ 3 is necessary for an anthelmintic activity, whereas a DP > 4 does not lead to a further increased inhibitory effect against the helminths. In summary, the findings rationalize the traditional use of C. mucronatum and provide further insight into the anthelmintic activity of condensed tannins.