In vitro antibacterial and cytotoxic activity of leaf extracts of Centella asiatica (L.) Urb, Warburgia salutaris (Bertol. F.) Chiov and Curtisia dentata (Burm. F.) C.A.Sm - medicinal plants used in South Africa

Abstract

BackgroundCompounds having both anticancer and antimicrobial activity have promising therapeutic potential due to their selective cytotoxicity and their potential to reduce the occurrence of bacterial and fungal infections in immune-compromised cancer patients. In our quest to find new antimicrobial agents with potent anticancer activity, the biological potential of leaves from the three medicinal plants Centella asiatica, Warburgia salutaris and Curtisia dentata as used by Zulu traditional healers for the treatment of cancer is investigated.MethodsExtracts were assayed for antibacterial activity using the agar well diffusion and micro plate dilution assay. In addition, minimum bactericidal concentrations (MBC), lactate dehydrogenase (LDH) release assay and rhodamine 6G intake assay were used to ascertain the antibacterial activity. The cytotoxic effects of the plant extracts were determined using tetrazolium-based colorimetric (MTT) cell proliferation assay against MCF-7, human colorectal carcinoma cells (Caco-2), A549 and HeLa cancerous cell lines.ResultsThe acetone extracts from Waburgia salutaris revealed noteworthy anti-proliferative effect yielding IC50 value of 34.15 μg/ml against MCF-7 cell line, while acetone extract from Curtisia dentata significantly (P ≤ 0.05) revealed promising IC50 values of 41.55, 45.13, 57.35 and 43.24 μg/ml against A549, HeLa, CaCo-2 and MCF-7 cell lines. The extracts further revealed a broad-spectrum antibacterial activity against bacterial strains used in the study. An acetone extract from W. salutaris revealed the highest zone of inhibition and the lowest minimum inhibitory concentration (MIC) of 21.0 mm and 0.16 mg/ml respectively against Staphylococcus aureus. Methanol extract from W. salutaris and ethyl acetate extract from C. dentata revealed 53% inhibition of R6G inside the cell against Staphylococcus aureus and Escherichia coli respectively in a cytosolic lactate dehydrogenase assay, suggesting that the mode of action of such extracts may be through efflux pump.ConclusionsOverall, the extracts had good antibacterial activity and anti-proliferative effects against selected cancerous cell lines. Given the good antibacterial activity of the extracts the plants may act as an immune booster and prevent infection in immunosuppressed cancer patients. This is further supported by the plants’ anti-proliferative potential, bacteriostatic, bactericidal properties and also their ability to block bacterial efflux pump systems.

Medicinal plants used in managing diseases of the respiratory system among the Luo community: an appraisal of Kisumu East Sub-County, Kenya

“…However, drowsiness in doses between 1200 and 5000 mg/kg was reported [77] The compounds isolated from the methanol stem bark fraction (resveratrol derivatives) were reported to have low cytotoxicity on prostate cancer cell lines [78]. The ethanol root extract was reported to be nontoxic in brine shrimp larvae [74] [84] in vitro (Hole plate diffusion method, microdilution method) [83], in vitro (Bioautography assay) [84] The acetone leaf extract was reported to be cytotoxic against cancer cell lines [85] Carica papaya L.…”

Plantas Medicinais e seus Compostos com Potencial Terapêutico no Tratamento do Câncer: Revisão Integrativa

“…De forma similar, outros estudos demonstraram que o lupeol apresentou atividade citotóxica para linhagens de câncer de mama, fígado e cólon, e pode se tornar um candidato promissor na terapia contra o câncer como medicamento, por causa da modulação na dinâmica mitocondrial, influenciando em processos que interferem na integridade da membrana, provocando apoptose. Contudo, será necessária ainda uma avaliação da posologia para aplicação em seres humanos em estudos posteriores, visto que os artigos apresentam ensaios in vitro e in vivo 28,84 .…”

Centella asiatica phenolic extract-mediated bio-fabrication of silver nanoparticles: characterization, reduction of industrially relevant dyes in water and antimicrobial activities against foodborne pathogens

“…The antimicrobial activities of extracts from the leaves and root of C. asiatica have been previously reported with MIC range of 10 to 20 mg mL À1 and 5 to >10 mg mL À1 . 46,48 As shown in Table 3, the green synthesized AgNPs demonstrated excellent antibacterial activity against the tested isolates with MIC of 0.625 to 1.249 mg mL À1 and MBC range of 2.498 to 9.994 mg mL À1 . The antimicrobial mechanisms of AgNPs are not elaborately understood, however it is suggested that the binding of the positively charge silver ions to the negatively charged bacterial cell wall components facilitates the penetration of the AgNPs across the membrane resulting in disruption of cell membrane, disintegration of DNA and interaction with cellular enzymes, transport proteins and other cytoplasmic components resulting in cell death.…”