In vitro and in vivo antioxidant potentials of the methanolic crude extract from Inula glomerata Oliv. & Hiern (Asteraceae) and Salacia kraussii (Harv.) Harv (Celastraceae)

Abstract

Reactive oxygen species are implicated in multiple pathological conditions including erectile dysfunction. This study evaluated the in vitro and in vivo antioxidant potential of the methanolic extracts of Inula glomerata and Salacia kraussii. The plant materials were pulverized and extracted with methanol. The phytochemical analysis, ability of the crude extracts to scavenge free radicals (ABTS, DPPH, NO.) in vitro as well as the total phenolic and flavonoid contents was investigated. In vivo, antioxidant potentials of the crude extracts (50/250 mg/kg body weight) were determined in an erectile dysfunction rat model. The phytochemical analysis revealed that both plants contain flavonoids, tannins, terpenoids, and alkaloids. The crude extracts at varying degree of efficiency, scavenged ABTS and DPPH radicals. The crude extracts at low concentrations (50 mg/kg b.w) significantly (p<0.05) diminished the level of malondialdehyde, augmented catalase activities and elevated glutathione levels. However, SOD activities were significantly boosted in a dose-dependent manner by the crude extracts. Therefore, I. glomerata and S. kraussii possess antioxidant properties, hence, can serve as a therapeutic modality in the treatment of oxidative stress-induced erectile dysfunction.

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“…Finally, the 6% yield of I. glomerata Oliv. and Hiern was lower than the 8.5% reported by Ojo et al [8], who used 17% v/v methanol as a solvent. According to Chigayo et al [32] and Che Sulaiman et al [34], solvents with lower than 80% v/v methanol content may not be as polar, preventing them from extracting most of the polar organic phytochemicals.…”

“…According to Chigayo et al [32] and Che Sulaiman et al [34], solvents with lower than 80% v/v methanol content may not be as polar, preventing them from extracting most of the polar organic phytochemicals. Therefore, the higher percent yield obtained by Ojo et al [8] could not be due to the low (17% v/v) methanol content of the solvent. The higher yield obtained could be due to differences in ages of plants, drying processes, geographical locations or soil types [20,21,23,43].…”

“…A total phenolic content of 50.2 mg GAE/g DW for P. thonningii (Schumach) Milne-Redh was reported by Alagbe [20], which result is less than the 1982 ± 2 mg GAE/g DW value obtained in this study. In addition, Ojo et al [8] reported a TPC value of 0.08 mg GAE/g DW for I. glomerata Oliv. and Hiern, which is also lower than the 780 ± 4 mg GAE/g DW obtained in this study.…”

“…stem bark, which is also lower than 4602 ± 32 mg GAE/g DW. During extractions, Alagbe [20] used diethyl ether, while Ojo et al [8] and Nantongo et al [25] used commercial-grade methanol with no water added. The usage of solvents that are so different from the 80% v/v used in our study might have contributed to the low TPC values, as diethyl ether is less polar than 80% v/v methanol.…”