Antioxidant, antitumor and antimicrobial activities of the crude extract and compounds of the root bark of Allanblackia floribunda

Bakuchiol nanoemulsion loaded electrospun nanofibers for the treatment of burn wounds

The present work aims to develop and evaluate the wound healing potential of bakuchiol nanoemulsion loaded electrospun scaffolds. Since oxidative stress and microbial burden leads the burn wounds to become chronic and fatal to patients, a phytoconstituent, bakuchiol (BAK), was screened on the basis of antioxidant and antimicrobial potential which also defined its dose. Furthermore, BAK was incorporated into a nanoemulsion to enhance its therapeutic efficacy, reduce its dosage frequency, and maximize its stability. The present study is inclined towards the collaborative interaction of natural products and novel drug delivery systems to develop safe and therapeutically efficient systems for burn wound healing. The optimized nanoemulsion showed excellent antioxidant and antimicrobial potential against wound susceptible pathogens, i.e., Candida albicans and Methicillin-resistant Staphylococcus aureus which was further loaded into gelatin based hydrogel and nanofibrous scaffold system. The mesh structure of scaffolds was chosen as a suitable carrier system for wound healing process not only because it offers resemblance to skin's anatomy but is also capable of providing uniform distribution of wound biomarkers across the skin. The prepared nanofibers were assessed for their analgesic, anti-inflammatory, and wound healing potential which was observed to be significantly better than its gel formulation.

In silico investigation of phytoconstituents from Cameroonian medicinal plants towards COVID-19 treatment

In silico studies performed on the metabolites of four Cameroonian medicinal plants with a view to propose potential molecules to fight against COVID-19 were carried out. At first, molecular docking was performed for a set of 84 selected phytochemicals with SARS-CoV-2 main protease (PDB ID: 6lu7) protein. It was further followed by assessing the pharmacokinetics and pharmacological abilities of 15 compounds, which showed low binding energy values. As the screening criteria for their ADMET properties were performed, only two compounds have shown suitable pharmacological properties for human administration which were shortlisted. Furthermore, the stability of binding of these compounds was assessed by performing molecular dynamics (MD) simulations. Based on further analysis through molecular dynamics simulations and reactivity studies, it was concluded that only the Pycnanthuquinone C (17) and the Pycnanthuquinone A (18) extracted from the Pycnanthus angolensis could be considered as candidate inhibitors for targeted protein. Indeed, we expect that these compounds could show excellent in vitro and in vivo activity against SARS-CoV-2.

Traditional Medicinal Plants as a Source of Antituberculosis Drugs: A System Review

Medicinal plants are the chief components in the different oriental formulations in different traditional medical systems worldwide. As a thriving source of medicine, the medicinal plants with antituberculosis (TB) properties inspire the pharmacists to develop new drugs based on their active components or semimetabolites. In the present review, the anti-TB medicinal plants were screened from the scientific literatures, based on the botanical classification and the anti-TB activity. The obtained anti-TB medicinal plants were categorized into three different categories, viz., 159 plants critically examined with a total 335 isolated compounds, 131 plants with their crude extracts showing anti-TB activity, and 27 plants in literature with the prescribed formula by the traditional healers. Our systemic analysis on the medicinal plants can assist the discovery of novel and more efficacious anti-TB drugs.

Allanblackia floribunda Seed Extract Attenuates the Ethanol-Induced Gastric Ulcer in Rats via the Inhibition of TNF-α and INF-γ Levels and Modulation in the Expression of Ki67 Protein

Allanblackia floribunda has been used to treat an upset stomach in African traditional medicine, but its efficacy and safety have not been scientifically studied. The present research is aimed at assessing the antiulcer property of the seed extract of the plant to validate its traditional claim. Rats were pretreated with three doses of aqueous extract of A. floribunda (AFE) at 30, 100, and 300 mg/kg or omeprazole 10 mg/kg for 1 hr before the acute gastric ulcer was induced by oral administration of 5 mL/kg of 98% ethanol. The animals were sacrificed under anesthesia, and the stomach and blood were collected. The gross histology of the stomach, percentage protection conferred by the treatment, gastric pH, and serum TNF-α and INF-γ were assessed as well as the expression of Ki67 antigens. The antioxidant properties as well as the acute toxicity profile of the plant extract were also assessed. The results show that A. floribunda conferred significant protection on the rats against gastric ulceration with % protection of 46.15, 57.69, and 65.38 for AFE 30, 100, and 300 mg/kg, respectively, as well as 69.23% for omeprazole 10 mg/kg. The plant extract caused marked reductions in gastric pH, TNF-α, and INF-γ with statistical significance (p < 0.001) for AFE 300 mg/kg and omeprazole 10 mg/kg. Also, the plant showed good antioxidant activity comparable to gallic acid. Furthermore, the plant extract modulated the expression of Ki67 antigens. All animals survived the 14-day delayed toxicity test with no significant differences in physical, hematological, and biochemical parameters between rats orally administered with supratherapeutic doses of AFE (5000 mg/kg) or normal saline. The study established that the gastroprotective effect of the seed extract of A. floribunda is attributable to its antisecretory, antioxidant, and anti-inflammatory properties. Additionally, the plant was found to promote ulcer healing via the modulation of the expression Ki67 and was safe at supratherapeutic doses.

Synthesis and Biological Evaluation of Four New Ricinoleic Acid-Derived 1-O-alkylglycerols

A series of novel substituted 1-O-alkylglycerols (AKGs) containing methoxy (8), gem-difluoro (9), azide (10) and hydroxy (11) group at 12 position in the alkyl chain were synthesized from commercially available ricinoleic acid (12). The structures of these new synthesized AKGs were established by NMR experiments as well as from the HRMS and elementary analysis data. The antimicrobial activities of the studied AKGs 8-11 were evaluated, respectively, and all compounds exhibited antimicrobial activity to different extents alone and also when combined with some commonly used antibiotics (gentamicin, tetracycline, ciprofloxacin and ampicillin). AKG 11 was viewed as a lead compound for this series as it exhibited significantly higher antimicrobial activity than compounds 8-10.

Bioactive properties and phytochemical assessment of Bacupari-anão (Garcinia brasiliensis Mart.) leaves native to Rondônia, Brazil

Leaf fractions of Garcinia brasiliensis were evaluated concerning their antioxidant, antimicrobial, anti-inflammatory and cytotoxic properties, and the most active fraction was then fully characterized regarding its phenolic composition using HPLC-DAD-ESI/MSn. The ethyl acetate fraction from partitioning of the methanolic leaf extract revealed a strong antioxidant activity that was comparable to Trolox, the positive control. This fraction was also able to show a significant antimicrobial activity against Gram-positive and Gram-negative bacteria and the fungus Candida albicans. However, the dichloromethane fraction was found to present the highest anti-inflammatory (83 ± 9 μg mL-1) and cytotoxic activities, thus presenting slight toxicity using a non-tumor cell line. Regarding the phenolic profile, the ethyl acetate fraction presented twelve flavonoids, with morelloflavone-7''-O-glucoside (52.1 ± 0.4 mg g-1) and gardinia biflavonoid 2a glucoside (27.5 ± 0.2 mg g-1) being the major compounds identified. These results indicate that leaves of G. brasiliensis might be a potential source of natural biomolecules for pharmaceutical and medicinal applications.

Phytoconstituents and Biological Activities of Garcinia Dulcis (Clusiaceae): A Review

Garcinia dulcis (Roxb.) Kurz is a tropical fruit tree native to Southeast Asia where it has a long history of use as a traditional medicine for the treatment of ailments such as lymphatitis, parotitis, struma, scurvy, cough, and sore throat. Despite its medicinal values, this plant is not well known and rarely found nowadays. Research on the phytochemical constituents and biological activities of G. dulcis have demonstrated that various parts of the plant contain an abundance of bioactive compounds mainly xanthones and flavonoids, with significant pharmacological properties such as anti-atherosclerosis, anti-bacterial, anti-cancer, anti-hypertension, and anti-malarial. In the present review, current knowledge of the phytochemistry of G. dulcis and biological activities of its active constituents based on the available literature are summarized in order to explore application potentials and prospective research works on this plant.

Polyphenols from Allanblackia floribunda seeds: Identification, quantification and antioxidant activity

Oil rich seeds of Allanblackia floribunda, a tree from tropical Africa, have traditionally been used in food preparation. Furthermore, the therapeutic properties of various parts of this tree have long been exploited in traditional medicine. As both food and pharmaceutical industries show growing interest in tropical tree crops, this study aimed to investigate whether A. floribunda seeds could also be used as a source of potentially bioactive compounds. The polyphenol profile revealed six predominant compounds which were identified by HPLC-PDA-ESI/MSⁿ as the biflavonoids morelloflavone, Gb-2a and volkensiflavone and their respective glucosides. A range of less abundant flavones, flavonols and flavan-3-ols was also detected. All six major compounds showed antioxidant activity, with the activity of morelloflavone, its glucoside and Gb-2a-glucoside comparable with that of ascorbic acid. The main compounds accounted for approximately 10% of dry weight, making the seeds used for oil production a rich source of biflavonoids as a by-product.

Allanblackia floribunda Oliv.: An aphrodisiac plant with vasorelaxant properties

ETHNOPHARMACOLOGICAL RELEVANCE

Allanblackia floribunda Oliv. is one of the most commonly used medicinal plant in Cameroon. The stem bark of the plant is traditionally used for its aphrodisiac and antihypertensive properties.

AIM OF THE STUDY

To validate the traditional uses of Allanblackia floribunda stem bark ethanol extract through the evaluation of their aphrodisiac and vasorelaxant properties.

MATERIALS AND METHODS

The extract's ability to increase sexual desire and the frequencies of erection (mount), intromission and prolonged latency of ejaculation were studied on adult male rats. The vasodilator effect was investigated using isolated rat aorta rings. Tests were conducted using fractions obtained by reverse phase column-chromatography (CC), after the acquisition of the HPLC fingerprint of the ethanol extract, resulted the most active in previous studies.

RESULTS

The CC allowed the isolation of five fractions whose aphrodisiac and vasodilator activities were tested and compared with those of the whole extract. Four compounds were identified and characterized, three of them, Fukugiside, Morelloflavone and Volkensiflavone, are secondary metabolites known to be in Allanblackia floribunda; the fourth, Spicataside, is a biflavonoid glycoside known to be present in the genus Garcinia but never found neither in Allanblackia floribunda nor in Allanblackia genus. The crude ethanolic extract (CEE) induced a relaxation on aorta rings with EC₅₀=11±2μg/mL and Morelloflavone displayed a similar activity with EC₅₀=42±6μg/mL; for all the other compounds only the vasodilation % at the maximum concentration assessable (90μg/mL) was determined: 30±8 (Fukugiside), 24±6 (Spicataside), 33±4 (Morelloflavone+Volkensiflavone), 47±1 (Volkensiflavone). Regarding the activity on male sexual behaviour, only CEE and Fukugiside showed activity in the 9 parameters evaluated.

CONCLUSIONS

These results may support the traditional uses of Allanblackia floribunda as aphrodisiac plant with antihypertensive properties suggesting the phytocomplex as responsible for the claimed activity.

Cytotoxicity of seven naturally occurring phenolic compounds towards multi-factorial drug-resistant cancer cells

INTRODUCTION

In medical oncology, multi-drug resistance (MDR) of cancer cells continues to be a major impediment. We are in quest of novel anti-proliferative agents to overcome drug-resistant tumor cells.

METHODS

In the present study, we investigated the cytotoxicity of 7 naturally occurring phenolic compounds including two isoflavonoids alpinumisoflavone (1) and laburnetin (2), one biflavonoid amentoflavone (3), three lignans pycnanthulignene A (4), pycnanthulignene B (5), and syringaresinol (7) and one xanthone, euxanthone (6) against 9 drug-sensitive and MDR cancer cell lines. The resazurin reduction assay was used to evaluate the cytotoxicity of these compounds, whilst caspase-Glo assay was used to detect caspase activation. Cell cycle, mitochondrial membrane potential (MMP) and levels of reactive oxygen species (ROS) were all analyzed via flow cytometry.

RESULTS

The IC50 values for the investigational phenolics ranged from 5.91 µM (towards leukemia CEM/ADR5000 cells) to 65.65 µM (towards drug-resistant breast adenocarcinoma MDA-MB-231-BCRP cells) for 1, 27.63 µM (towards leukemia CCRF-CEM cells) to 107.57 µM (towards MDA-MB-231-pcDNA cells) for 2, from 5.84 µM (towards CEM/ADR5000 cells) to 65.32 µM (towards colon carcinoma HCT116 (p53(-/-)) cells) for 4 and 0.20 µM (towards CCRF-CEM cells) to 195.12 µM (towards leukemia CEM/ADR5000) for doxorubicin. Phenolics 3, 5, 6 and 7 displayed selectivity cytotoxic effects on cancer cells lines. Compounds 1 and 4 induced apoptosis in CCRF-CEM cells, mediated by loss of MMP and increase ROS production.

CONCLUSIONS

The studied phenolics and mostly isoflavonoid 1 and lignan 4 are potential cytotoxic natural products that deserve more investigations to develop novel antineoplastic drugs against multifactorial drug-resistant cancers.

Antiplasmodial activity of some phenolic compounds from Cameroonians Allanblackia

BACKGROUND

Plasmodium falciparum, one of the causative agents of malaria, has high adaptability through mutation and is resistant to many types of anti-malarial drugs. This study presents an in vitro assessment of the antiplasmodial activity of some phenolic compounds isolated from plants of the genus Allanblackia.

METHODS

Tests were performed on well plates filled with a fixed parasitized erythrocytes volume. Compounds to be tested were then added in wells. After incubation, tritiated hypoxanthine is added and the plates were returned to the incubator. After thawing, the nucleic acids are collected. Inhibitory Concentration 50 (IC50) was determined by linear interpolation.

RESULTS

From Allanblackia floribunda, have been isolated and characterized 1,7-dihydroxyxanthone 1, macluraxanthone 4, morelloflavone 9, Volkensiflavone 10 and morelloflavone 7-O-glucoside 11; from Allanblackia monticola, α-mangosine 2, rubraxanthone 3, allaxanthone C 5, norcowanine 6, tovophiline A 7, allaxanthone B 8 and from Allanblackia gabonensis, 1,7-dihydroxyxanthone 1. Six of them were evaluated for their antimalarial properties. The most active compound, macluraxanthone, presented a very interesting activity, with an IC50 of 0.36 and 0.27 µg/mL with the F32 and FcM29 strains respectively.

CONCLUSION

This work confirms that species of Allanblackia genus are medicinally important plants containing many biologically active compounds that can be used effectively as antiplasmodial.

In vitro anticancer screening of 24 locally used Nigerian medicinal plants

BACKGROUND

Plants that are used as traditional medicine represent a relevant pool for selecting plant candidates that may have anticancer properties. In this study, the ethnomedicinal approach was used to select several medicinal plants native to Nigeria, on the basis of their local or traditional uses. The collected plants were then evaluated for cytoxicity.

METHODS

The antitumor activity of methanolic extracts obtained from 24 of the selected plants, were evaluated in vitro on five human cancer cell lines.

RESULTS

Results obtained from the plants screened indicate that 18 plant extracts of folk medicine exhibited promising cytotoxic activity against human carcinoma cell lines. Erythrophleum suaveolens (Guill. & Perr.) Brenan was found to demonstrate potent anti-cancer activity in this study exhibiting IC(50) = 0.2-1.3 μg/ml.

CONCLUSIONS

Based on the significantly potent activity of some plants extracts reported here, further studies aimed at mechanism elucidation and bio-guided isolation of active anticancer compounds is currently underway.