Phytochemical, antioxidant, and functional group analyses of South African Evolvulus alsinoides (L.) L

Evolvulus alsinoides (L.) L. (Convolvulaceae) is a forb species that is highly valued in traditional medicine for its memory-enhancing effects, and a range of other ethnomedicinal properties. However, there are no studies on the phytochemical composition and antioxidant activities of E. alsinoides collected in South Africa. The present study was designed to investigate the phytochemical contents and antioxidant properties of aqueous and ethanolic plant extracts of E. alsinoides collected from the Limpopo Province of South Africa. The phytochemical contents were determined using spectrophotometric and colorimetric methods, while the antioxidant activities were determined using three in vitro antioxidant ([2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), and Ferric reducing antioxidant power (FRAP)] assays. Additionally, the functional groups present in the extracts were analyzed using Fourier-transform infrared (FTIR) spectroscopy. Results revealed that the ethanolic extracts of E. alsinoides gave the highest content of total phenol (17.07 ± 2.28 mg GAE/g DW extract), total flavonoid (82. 44 ± 0.93 mg QE/g DW extract), and proanthocyanidin (32. 98 ± 2.10 mg CE/g DW extract). The total alkaloid and saponin quantification of the crude extract of E. alsinoides gave mean percentage values of 2.6 ± 0.2% and 33.7 ± 0.00%, respectively. The ethanol extract had the highest DPPH scavenging ability (IC₅₀ value: 0.4367 mg/mL), ABTS scavenging ability (IC₅₀ value: 0.099 mg/mL) and the best ferric reducing antioxidant power (138.16 ± 3. 27 mg TE/ g). The total phenolic, flavonoid, and proanthocyanidins contents positively correlated with DPPH and ABTS activities. The spectral data of FTIR analysis of E. alsinoides extracts revealed the presence of functional characteristic groups of carboxylic acids, aromatic amines, alkanes, phenols, alkynes, hydroxy, alcohols, and sulfoxide, which could contribute to the medicinal properties of this plant species. The results of the study justify the usage of E. alsinoides in folkloric medicine and can be explored further for pharmaceutical plant-based products.