Comparative evaluation of cytotoxic, antimicrobial and antioxidant activities of the crude extracts of three species grown in Saudi Arabia.
Journal:
Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society
Published Date:
Sep 25, 2018
Abstract
Natural products from medicinal plants represent major resource of novel therapeutic substances for combating serious diseases including cancers and microbial infections. The genus (Family: Labiatae) represents a large and widespread group of species with a diversity of traditional uses in treatment of various ailments. Therefore, this research study aimed to evaluate the cytotoxic, antimicrobial and antioxidant activities of three species growing in Saudi Arabia namely Hocst. ex Benth. JRI Wood and Andrews Moreover, this work focused on the isolation of the active constituents responsible for the activities from the most active species. The extracts were tested for their cytotoxic activity against three cancer cell lines (Hela, HepG2 and HT-29), using MTT-test, antimicrobial activity against Gram positive, Gram negative bacterial and fungal strains using broth micro-dilution assay for minimum inhibitory and bactericidal concentrations (MIC and MBC) and antioxidant activity using scavenging activity of DPPH radical and β-carotene-linoleic acid methods. The ethanolic extracts of the species showed remarkable cytotoxic activity against all cancer cell lines with IC values ranging between 10.1 ± 0.33 to 102.6 ± 8.66 μg/mL and a great and antimicrobial activity with MIC values between 62.5 and 250 µg/mL. In addition, the three species showed almost moderate antioxidant activity. The most interesting cytotoxic and antimicrobial results were observed with the extract of Consequently, this extract was partitioned between water and hexane, chloroform and butanol and tested. The cytotoxic activity resided predominantly in the hexane and chloroform fractions. The analysis of the chloroform fraction led to the isolation of four diterpenoid compounds, two of labdane- and two of abietane-type, which were identified as coleonol B, forskolin, sugiol and 5,6-dehydrosugiol. Purification of the -hexane fraction led to isolation of a major abietane-type diterpene, which was identified as ferruginol. Sugiol, 5,6-dehydrosugiol and ferruginol were isolated for the first time from in this study. The isolated diterpenoids showed variable cytotoxic effects with IC values between 15.1 ± 2.03 and 242 ± 13.3 µg/mL, a great antimicrobial activity with MIC values between 15.6 and 129 µg/mL and a total antioxidant activity ranging from 23.1 ± 2.9 to 69.2 ± 3.8%.
Authors
Keywords
No keywords available for this article.