Prostate cancer disparity, chemoprevention, and treatment by specific medicinal plants

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Prostate cancer (PC) is one of the most common cancers in men. The global burden of this disease is rising. Its incidence and mortality rates are higher in African American (AA) men compared to white men and other ethnic groups. The treatment decisions for PC are based exclusively on histological architecture, prostate-specific antigen (PSA) levels, and local disease state. Despite advances in screening for and early detection of PC, a large percentage of men continue to be diagnosed with metastatic disease including about 20% of men affected with a high mortality rate within the African American population. As such, this population group may benefit from edible natural products that are safe with a low cost. Hence, the central goal of this article is to highlight PC disparity associated with nutritional factors and highlight chemo-preventive agents from medicinal plants that are more likely to reduce PC. To reach this central goal, we searched the PubMed Central database and the Google Scholar website for relevant papers. Our search results revealed that there are significant improvements in PC statistics among white men and other ethnic groups. However, its mortality rate remains significantly high among AA men. In addition, there are limited studies that have addressed the benefits of medicinal plants as chemo-preventive agents for PC treatment, especially among AA men. This review paper addresses this knowledge gap by discussing PC disparity associated with nutritional factors and highlighting the biomedical significance of three medicinal plants (curcumin, garlic, and Vernonia amygdalina) that show a great potential to prevent/treat PC, as well as to reduce its incidence/prevalence and mortality, improve survival rate, and reduce PC-related health disparity

Antimycobacterial activity of selected medicinal plants extracts from Cameroon

New drugs are highly needed to control mycobacterial infections. This study aimed at screening ethnobotanically selected plants extracted using organic solvents for their antimycobacterial activity. In vitro assays were performed on Mycobacterium smegmatis, Mycobacterium avium, Mycobacterium bovis Bacille Calmette Guerin (BCG), Mycobacterium tuberculosis and Mycobacterium ulcerans using the Resazurin Microtiter Assay. Cytotoxicity was assessed on Human lung fibroblast cells (MRC5) and bone marrow-derived macrophages (BMDM) using the MTS tetrazolium assay. The most promising extract from Annickia chlorantha stem bark (ACsbI) was tested for intracellular antimycobacterial activity against M. smegmatis using infected BMDM. Sixty crude extracts, 19 fractions, and 2 purified compounds were obtained from 19 Cameroonian medicinal plants. Results showed that crude extracts mainly inhibited BCG, while interface fractions from A. chlorantha stem bark (ACsbI) and stem (ACstI) displayed the strongest activity against M. ulcerans, with Minimal Inhibitory Concentrations (MIC) of 1.95 and 7.81 µg/ml respectively. Two compounds purified from Sorindeia juglandifolia fruits (SJfr 3.6 and SJfr 4.5) showed activity against BCG and M. ulcerans at 3.9 µg/ml and 62.5 µg/ml respectively. Finally, ACsbI showed no toxicity against MRC5 cells and BMDM and inhibited the growth of intracellular M. smegmatis. The results achieved in this investigation support the traditional to use of these plants and the need to investigate them in deeper details to be able to find alternatives for the existing antimycobacterial drugs

Hypoglycemic Properties of the Aqueous Extract from the Stem Bark of Ceiba pentandra in Dexamethasone-Induced Insulin Resistant Rats

Parts of Ceiba pentandra are wildly used in Africa to treat diabetes and previous works have demonstrated their in vivo antidiabetic effects on type 1 diabetes models. In addition, it has been recently shown that the decoction and the methanol extract from the stem bark of C. pentandra potentiate in vitro, the peripheral glucose consumption by the liver and skeletal muscle slices. But nothing is known about its effect on type II diabetes, especially on insulin resistance condition. We investigated herein the antihyperglycemic, insulin-sensitizing potential, and cardioprotective effects of the dried decoction from the stem bark of Ceiba pentandra (DCP) in dexamethasone-induced insulin resistant rats. DCP phytochemical analysis using LC-MS showed the presence of many compounds, including 8-formyl-7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthaquinone, 2,4,6-trimethoxyphenol, and vavain. Wistar rats were given intramuscularly (i.m.) dexamethasone (1 mg/kg/day) alone or concomitantly with oral doses of DCP (75 or 150 mg/kg/day) or metformin (40 mg/kg/day) for 9 days. Parameters such as body weight, glycemia, oral glucose tolerance, plasma triglycerides and cholesterol, blood pressure, and heart rate were evaluated. Moreover, cardiac, hepatic and aortic antioxidants (reduced glutathione, catalase, and superoxide dismutase), malondialdehyde level, and nitric oxide content were determined. DCP decreased glycemia by up to 34% and corrected the impairment of glucose tolerance induced by dexamethasone but has no significant effect on blood pressure and heart rate. DCP reduced the total plasma cholesterol and triglycerides as compared to animals treated only with dexamethasone. DCP also increased catalase, glutathione, and NO levels impaired by dexamethasone, without any effect on SOD and malondialdehyde. In conclusion, the decoction of the stem bark of Ceiba pentandra has insulin sensitive effects as demonstrated by the improvement of glucose tolerance, oxidative status, and plasma lipid profile. This extract may therefore be a good candidate for the treatment of type II diabetes

Phytochemical composition and in vitro effects of the ethyl acetate bark extract of Distemonanthus benthamianus Baillon (Caesalpiniaceae) on Staphylococcus aureus and Streptococcus agalactiae

Distemonanthus benthamianus is a tree used in traditional African medicine to treat bacterial, fungal and viral infections. The pasty phase and the granular phase obtained from the ethyl acetate bark extract of D. benthamianus were tested for antimicrobial purposes on Staphylococcus aureus and on Streptococcus agalactiae alone and in combination with erythromycin. Only the pasty phase of the extract was active against the above bacteria (MIC = 1024 µg/mL ; MBC = 4096 µg/mL). The MIC of erythromycin against S. aureus and S. agalactiae was 8 µg/mL and 4 µg/mL, respectively. The MBC of erythromycin was 32 µg/mL against S. aureus and 8 µg/mL against S. agalactiae. The combination of that active phase (256 µg/mL) with erythromycin (1 µg/mL) was synergistic and the ratio MBC / MIC was 4 suggesting that the plant extract may be a bactericidal agent. Phytochemical analysis revealed the presence of flavonoids and phenolic compounds in the pasty phase of the plant extract and the absence of sterols, triterpenes and alkaloids in the same phase. In contrast, the granular phase contained all the above compounds except flavonoids. This result suggests that the active principle may belong to the class of flavonoids. Keywords: Distemonanthus benthamianus, MBC, MIC, Staphylococcus aureus, Streptococcus agalactiae. RESUME Distemonanthus benthamianus est un arbre utilisé en médecine traditionnelle africaine pour traiter les infections bactériennes et virales, ainsi que les mycoses. Les effets antibactériens des phases pâteuse et granulaire obtenues à partir de l'extrait à l'acétate d'éthyle de l'écorce de D. benthamianus ont été testés sur Staphylococcus aureus et sur Streptococcus agalactiae seule ou en association avec l'érythromycine. Seule la phase pâteuse a été active sur les bactéries évoquées (CMI = 1024 µg/mL ; CMB = 4096 µg/mL). La CMI de l'érythromycine vis à vis de S. aureus et de S. agalactiae a été de 8 µg/mL et de 4 µg/mL, respectivement. La CMB de l'érythromycine a été de 32 µg/mL sur S. aureus et de 8 µg/mL sur S. agalactiae. L'association de la phase pâteuse (256 µg/mL) avec l'érythromycine a été synergique et le rapport CMB / CMI a été de 4. Ceci montre que cet extrait de plante pourrait être un agent bactéricide. L'analyse phytochimique a révélé la présence des flavonoïdes et des composés phénoliques dans la phase pâteuse de l'extrait et l'absence des stérols, des triterpènes et des alcaloïdes dans cette même phase. Par contre, tous les composés sus-cités à l'exception des flavonoïdes ont été notés dans la phase granulaire. Ce résultat suggère que le principe actif appartiendrait à la classe des flavonoïdes. Mots clés: Distemonanthus benthamianus, CMB, CMI, Staphylococcus aureus, Streptococcus agalactiae Cameroon Journal of Experimental Biology Vol. 1(1) 2005: 50-5

Herbal Cosmetics Knowledge of Arab-Choa and Kotoko Ethnic Groups in the Semi-Arid Areas of Far North Cameroon: Ethnobotanical Assessment and Phytochemical Review

The plant-based traditional knowledge of many Cameroonian populations concerning beauty and skin care is still poorly documented, yet they are real resources of innovation and economic development. The aim of this study is to document the indigenous knowledge of Choa Arab and Kotoko ethnic group in Kousséri (Far North Region of Cameroon) about plants used for cosmetics. Ethnobotanical data collected among key informants revealed a total of 13 plants species belonging to 12 families used by local people. Canarium schweinfurthii Engl and Santalum album L. obtained the highest frequency of citation. Trees are the most abundant life forms, while barks and seeds are the most frequently used parts. More than 40% of recorded plants are used for skin care. The cosmetic allegations of recorded plants include: dermatology, anti-cancers, antioxidant agent, perfume, anti-inflammatory, antimicrobial, wounds healing activity, skin lightening, dental caries, astringent and hair care. They all contain various phytochemicals that are of interest in cosmetics. Despite the strong relationship between the Choa Arab and Kotoko people and herbal cosmetic ingredients, these plants are still less investigated for their cosmetic application. The authors urge for the development of sustainable supply chain for plants with potentials as cosmetics, involving local communities in the planning, implementation and monitoring process, following principles of Nagoya protocol on Access and Benefit Sharing

Costus afer Protects Cardio-, Hepato-, and Reno-Antioxidant Status in Streptozotocin-Intoxicated Wistar Rats

Medicinal plants are efficient modulators of oxidative stress associated with diabetes mellitus. This study evaluated the cardio-, reno-, and hepato-antioxidant status of hydroethanolic extract of Costus afer on streptozotocin-intoxicated diabetic rats. Experimental animals were daily administered with hydroethanolic extract of C. afer by oral intubation for eight weeks (60 days), after which the levels of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and lipid peroxidation marker (MDA) were evaluated in the heart, liver, and kidney homogenates. Plasma biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total protein, creatinine, and urea were determined. Meanwhile, parts of the heart, kidneys, and liver were histopathologically examined. Streptozotocin administration induced toxicity in the cardiac, hepatic, and renal tissues by stimulating significant increases (p<0.05) in the levels of CAT and SOD, GSH, and MDA. Similarly, significant increases (P<0.05) in the levels of ALT, AST, urea, and total protein were observed in streptozotocin treated rats, whereas decreases were observed in the levels of ALP, LDH, and creatinine. Following the treatments with C. afer hydroethanolic extract prevented the effect of streptozotocin by maintaining the tissue antioxidant status (CAT, SOD, GSH, and MDA) and the plasma biochemical parameters (AST, ALT, ALP, LDH, creatinine, and urea) towards the normal ranges. The histopathological examination revealed hepatovascular congestion and leucocyte infiltration as well as renovascular congestion, glomerulosclerosis, and tubular clarification in the untreated diabetic control and their absence in the group of animals treated with a high dose of C. afer extract. The findings of the present investigation suggest that C. afer possesses antioxidant activities capable of regulating drug induced tissue damage

Marine Algae as Source of Novel Antileishmanial Drugs: A Review

Leishmaniasis is a vector-borne neglected tropical disease caused by protozoan parasites of the Leishmania genus and transmitted by the female Phlebotomus and Lutzomyia sand flies. The currently prescribed therapies still rely on pentavalent antimonials, pentamidine, paromomycin, liposomal amphotericin B, and miltefosine. However, their low efficacy, long-course treatment regimen, high toxicity, adverse side effects, induction of parasite resistance and high cost require the need for better drugs given that antileishmanial vaccines may not be available in the near future. Although most drugs are still derived from terrestrial sources, the interest in marine organisms as a potential source of promising novel bioactive natural agents has increased in recent years. About 28,000 compounds of marine origin have been isolated with hundreds of new chemical entities. Recent trends in drug research from natural resources indicated the high interest of aquatic eukaryotic photosynthetic organisms, marine algae in the search for new chemical entities given their broad spectrum and high bioactivities including antileishmanial potential. This current review describes prepared extracts and compounds from marine macroalgae along with their antileishmanial activity and provides prospective insights for antileishmanial drug discovery

Essential Oils from Cameroonian Aromatic Plants as Effective Insecticides against Mosquitoes, Houseflies, and Moths

Recently, spices have attracted the attention of scientists and agrochemical companies for their potential as insecticidal and acaricidal agents, and even as repellents to replace synthetic compounds that are labeled with detrimental impacts on environment and human and animal health. In this framework, the aim of this study was to evaluate the insecticidal potential of the essential oils (EOs) obtained from three Cameroonian aromatic plants, namely Monodora myristica (Gaertn.) Dunal, Xylopia aethiopica (Dunal) A. Rich., and Aframomum citratum (J. Pereira) K. Schum. They were produced by hydrodistillation, with yields of 3.84, 4.89, and 0.85%, respectively. The chemical composition was evaluated by GC-MS analysis. The EOs and their major constituents (i.e., geraniol, sabinene, &alpha;-pinene, p-cymene, &alpha;-phellandrene, and &beta;-pinene) were tested against the polyphagous moth pest, i.e., Spodoptera littoralis (Boisd.), the common housefly, Musca domestica L., and the filariasis and arbovirus mosquito vector, Culex quinquefasciatus Say. Our results showed that M. myristica and X. aethiopica EOs were the most effective against M. domestica adults, being effective on both males (22.1 &micro;g adult&minus;1) and females (LD50: 29.1 &micro;g adult&minus;1). The M. myristica EO and geraniol showed the highest toxicity on S. littoralis, with LD50(90) values of 29.3 (123.5) and 25.3 (83.2) &micro;g larva&minus;1, respectively. Last, the EOs from M. myristica and X. aethiopica, as well as the major constituents p-cymene and &alpha;-phellandrene, were the most toxic against C. quinquefasciatus larvae. The selected EOs may potentially lead to the production of cheap and effective botanical insecticides for African smallholders, although the development of effective formulations, a safety evaluation, and an in-depth study of their efficacy on different insect species are needed

Antrocarines A-F, antiplasmodial ergostane steroids from the stem bark of Antrocaryon klaineanum.

During a study on the chemistry and biological activity of Antrocaryon klaineanum Pierre, six new sterols including 4,24(28)-ergostadiene-6alpha,7alpha-diol (1), 6alpha-methoxy-4,24(28)-ergostadiene-7alpha,20S-diol (2), 6alpha-methoxy-4,24(28)-ergostadien-7alpha-ol (3), 20S-hydroxy-24(28)-ergosten-3-one (4), 7alpha-hydroxy-4,24(28)-ergostadien-3-one (5), and 24(28)-ergostene-3beta,6alpha-diol (6) were characterized by physical and spectroscopic means. The known steroids 7 and 8 were also isolated. The crude extract and the isolated compounds were evaluated for their ability to inhibit the 3D7 strain of Plasmodium falciparum. Compounds 2, 3, and 8 showed potent activity while that of the crude extract was moderate