ABSTRACT

Thunbergia alata and Tabernaemontana coronaria are used in traditional and folklore medicine but not systematically studied for their traditional claims. Polyphenolics such as tannins and flavonoids are proven as powerful antioxidants and antiseptic agents to treat skin infections. The current investigation is aimed to determine the phenolic, flavonoid content, the antioxidant activity of Thunbergia alata and Tabernaemontana coronaria leaves. Total phenolic content was estimated by Folin–Ciocalteu colorimetric method taking gallic acid as standard. Whereas total flavonoid content was determined by Aluminum chloride colorimetric assay using Rutin as standard. The absorbance was measured at 760?nm and 510?nm, respectively. Antioxidant activity was measured by two In vitro methods (DPPH and NO free radical scavenging assay) using standard protocols, where Ascorbic acid served as a reference standard. Results disclosed that total phenolic content for the ethanol extracts of Tabernaemontana coronaria (95.25±2.06) and Thunbergia alata (62.74±1.28) was found to be higher than petroleum ether extracts. Similarly, of Tabernaemontana coronaria (25.64±1.92) is richer in flavonoids than Thunbergia alata (13.73±1.14). In DPPH assay, ethanol extract of Tabernaemontana coronaria (72.37%) is more effective to inhibit the free radicals than Thunbergia alata (61.72%) with IC50 values 50.06µg/ml & 74.77µg/ml respectively. Similarly, in NO free radical scavenging assay, ethanol extract of Tabernaemontana coronaria (75.37%) stood best among all to scavenge the free radicals with IC50 values 47.15µg/ml. The presence of various secondary metabolites alone or in combination may be responsible for the observed scavenging property. The quantity of the phenolic compounds and flavonoids can directly correlate to the exhibited activity. Keywords: Thunbergia alata, Tabernaemontana coronaria, antioxidant, total phenolic content, total flavonoid content, free radical scavenging, extraction
Publication date: 25/09/2021

https://ijbpas.com/pdf/2021/September/MS_IJBPAS_2021_SEPT_SPCL_10461.pdf

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https://doi.org/10.31032/IJBPAS/2021/10.9.1046