Date Published: January 2, 2019
Author(s): Mas Athira Johari, Heng Yen Khong.
Different solvent extracts of Pereskia bleo leaves were evaluated for total phenolic content (TPC) and antioxidant activities based on the Folin–Ciocalteu test and DPPH scavenging activities. The antibacterial activities against four bacteria, namely, Gram-positive bacteria: Streptococcus pyogenes ATCC 19615 (SP) and Staphylococcus aureus ATCC 29737 (SA) and Gram-negative bacteria: Escherichia coli ATCC 10536 (EC) and Pseudomonas aeruginosa ATCC 9027 (PA), were also performed based on the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. The findings demonstrated that both the methanolic and chloroform extracts displayed strong activities against SA, SP, EC, and PA while the hexane extract demonstrated the weakest activities towards all the four bacteria. The methanolic extract also exhibited higher TPC and possessed higher antioxidant activity with the IC50 value 33.83 µg/mL compared to the chloroform and hexane extracts. As such, the methanolic extract has a higher ability to scavenge free radical compared to other extracts. Due to the interesting result, activities are shown by the methanolic and chloroform crude extracts of P. bleo; hence, the study has been extended to the isolation of bioactive compounds to uncover its great potential as a natural source for antibacterial and antioxidant agents.
Medicinal plants have been used to promote human health, and it has been documented since ancient times. Even though accessibility to modern healthcare nowadays become faster and easier, still there are people who prefer to promote health by using fresh medicinal plants which are locally grown. For example, in the way to compliment the allopathic medicine, Malays prefer Jamu medicine and Chinese prefer Traditional Chinese medicine (TCM) while Indians prefer Ayurvedic medicine. Therefore, even though there is an abundance of modern medicine in the market, traditional medicine still maintained its popularity in the developing world.
The methanolic and chloroform extracts of P. bleo showed strong inhibition activity towards the tested bacteria SA, SP, PA, and EC. The methanolic extract exhibited highest TPC (40.82 mg GAE/g) and possess highest antioxidant activity (IC50 value 33.83 µg/mL) compared to chloroform and hexane extracts. Linear correlation among two parameters of the high TPC value which will give great antioxidant capacity are proved in this study where high antioxidant activity demonstrated by the methanolic extract is backed by the high TPC value. Due to the interesting results exhibited by the methanolic and chloroform extracts of P. bleo, the study has extended to the isolation of bioactive compounds to uncover its great potential natural source for antibacterial and antioxidant agents.