Evaluation of the Anti-Mycobacterial, Anti-Oxidative and Anti-Proliferative Activities of Rubia Cordifolia Ethanolic Leaf Extract Sub-Fractions in Human Lymphocytes and Neutrophils

Abstract

Background. Rubia cordifolia has been used to treat various diseases and exhibits antimicrobial, anti-inflammatory, analgesic and antidiarrheal activities. The plant has not been investigated for its anti-mycobacterial activity against virulent tuberculosis strains as well as cytotoxic and anti-oxidant activities in mononuclear cells and neutrophils. Methods. Ethanolic and dichloromethane leaf extract fractions of Rubia cordifolia (0.2-125µg/ml) were screened for anti-mycobacterial activity using a fluorescent microplate assay. The anti-oxidant activity of the fractions was tested using the radical scavenging assay, while their cytotoxicity to lymphocytes was measured using the WST-8 assay. Reactive oxygen species production by neutrophils exposed to fractions was tested using Cell Meter™ Fluorimetric ROS Assay kit. Results. The ethanolic leaf fractions exhibited overall superior anti-mycobacterial activity than the dichloromethane group and were further screened for anti-oxidant and cytotoxic activities. Ethanolic sub-fractions K2F-3.2, K2F-3.3 and K2F-3.4 showed significant antioxidant activities at concentration of 50 µg/ml to 200 µg/ml and higher in both the cell free-based radical scavenging activity and total reactive oxygen species production assays. For lymphocytes, the test agents showed anti-proliferative activity at 25 µg/ml to 200 µg/ml for sub-fraction K2F-3.3B and 50 µg/ml to 200 µg/ml for agents K2F-3.2 and K2F-3.4. Conclusion. The current study is the first to record the in vitro anti-mycobacterial, anti-oxidant and cytotoxic activities of Rubia cordifolia plant leaf extract sub-fractions using the given experimental setups and further research activities to identify the bioactive components are to be pursued.

Anti-Mycobacterial Activity of Medicinal Plant Extracts Used in the Treatment of Tuberculosis by Traditional Medicine Practitioners in Uganda

“…Methanolic extracts of Rubia cordifolia equally exhibited moderately high anti-mycobacterial activity against all M. tuberculosis strains used. Similar or higher activity was reported by Makgatho et al, in a study carried out in South Africa to evaluate R. cordifolia anti-mycobacterial activity [25]. Crude 80% etha-nolic and methanolic extracts of both plant species had their inhibitory concentrations ranging as low as 23 μg/mL to 750 μg/ml.…”

“…The antimycobacterial activity of standard drugs was superior to that of the crude plant extracts because the latter contains a mixture of bioactive constituents of which some might antagonize the effects of others. Isolation of active molecules increases the activity of these compounds as reported for Zanthoxylum leprieurii [21], Zanthoxylum capense [30] and R. cordifolia [25].…”

Combination Activity of Standard Antituberculosis Drugs and Extracts of Medicinal Plants Commonly Used in Traditional Treatment of Tuberculosis in Uganda

“…This nding was consistent with other standard anti-TB drugs studied against MDR strains. This is in tandem with other previous studies that indicated that extracts of Z. leprieurii and R. cordifolia inhibited the growth of the MDR strain of Mycobacterium tuberculosis [4,20,22].…”