Potency of Antioxidant Properties of Major Secondary Metabolite and #8206;from Stevia rebaudiana in a Comparison to Synthetic Antioxidants

Abstract

ABSTRACT:Bioactivit y-guided fracti onati on was perf ormed to eval uate t he anti oxidant ac tivit y of S tevi a rebaudiana B ert oni. T he met hanolic cr ude (MC) extract of leav es was fr acti onat ed using a m odified K upchan partiti oning m ethod. The antioxidant ac tivit y w as m easur ed f or t he MC and frac tions. Free radic al scav enging using 2, 2-Diphenyl-1-picryl-hydraz yl (D PPH) and tot al anti oxidant ac tivit y using phosphomol ybdenum c omplex m et hods wer e selec ted f or determinati on of t he anti oxidant activit y usi ng as corbic acid (A A) as a refer enc e. Preliminar y anti oxidant ac tivit y meas urem ents r ev eal ed t hat the dichloromethane frac tion w as of i nt erest . Cons equentl y, it was s ubject ed t o chrom at ographic s eparation and purification tec hniques. One m ajor pure c ompound w as isolat ed and its str uct ure elucid ation using NMR and HR MS c onfirmed it to b e 3' ,5, 7-trihydroxy-3, 4', 6-trimet hoxyflavone (cent aureidin). The IC 50 v alues of MC , butanol, m et hanol and dichlorom et hane fractions and c entaureidin (CT) wer e 120.6 ± 0. 58, 66. 5 ± 0. 49, 79. 5 ± 0. 44, 37.1 ± 0. 23, and 18. 4 ± 0. 44 µg/mL, r espectiv el y. The results wer e c ompar ed t o t hose of s ynt hetic antioxidants, but ylat ed hydroxyanisol e ( BH A) and but ylated hydroxyt oluene (BHT) wit h IC 50 values of 13. 7 ± 0. 09 and 33. 1 ± 1. 05 µg/mL, respectiv el y; w hile t hat of A A w as 6. 5 ± 0.25 µg/mL. T he hig hes t t ot al antioxidant ac tivit y eval uated b y t he p hosp hom ol ybdenum complex method was exhibited by t he purified compound (CT) with a v alue of 5028. 6 ± 645. 87 mg A A equiv alent/g sample. The stud y rev eals that c omponents of t his plant could b e a p otenti al alter native t o s ynt hetic antioxidants b y virtue of their anti oxidant properties and natur al origin. antioxidant activi t y; Ast erac eae; Stevia rebaudiana ; s ynthetic anti oxidant; nat ural antioxidant; Cent aur eidin.

Screening and evaluation of cytotoxicity and antiviral effects of secondary metabolites from water extracts of Bersama abyssinica against SARS-CoV-2 Delta

“…The presence of 2,4-di-tert-butylphenol in water extract could have contributed to activity against SARS-CoV-2, which is reported by other studies [ 45 , 46 ] and presence of 7,8-Dihydroxy-4-methylcoumarin and 2,3, 6-trimethoxyflavone in the same extract have increased activity against SARS-CoV-2, which was reported to have antioxidant properties [ 47 , 48 ], enhancing viral inhibition. In addition, 4-formyl-2-methoxyphenyl propionate was also identified in water extract which has various pharmacological uses including anticardiovasular, antioxidant and anti-inflammatory [ 49 ] that would have enhanced inhibition in SARS-CoV-2 B1.…”

Screening and Evaluation of Cytotoxicity and Antiviral Effects of Secondary Metabolites from Water Extracts of Bersama abyssinica against SARS-CoV-2 Delta

“…The water extract of B. abyssinica yielded polyphenols especially the coumarin and avonoids which are reported to have high antiviral activity against Corona virus [26]. High antiviral activity from water extract could be due to presence of 2,4-di-tert-butylphenol that is well studied with antiviral activity [27,28] and strong antioxidant properties of 7,8-Dihydroxy-4-methylcoumarin and 2,3, 6-trimethoxy avone [29,30], enhancing viral inhibition. In addition, 4-formyl-2-methoxyphenyl propionate identi ed in water extract has various pharmacological uses including anticardiovasular and anti-in ammatory [31] that would enhance inhibition in SARS-CoV-2…”