Toxicological Evaluation, Ultrasound-Assisted Phytochemicals, Antioxidant, GC–MS, FTIR, and In Vivo Analysis of Hibiscus rosa-sinensis Flowers

Abstract

The application of medicinal plants in the healthcare system is a centuries-old practice, which is proving beneficial to communities. Hibiscus rosa-sinensis, a flowering plant in the family Malvaceae, is used for both ornamental and medicinal purposes. The current research study evaluates ultrasound-assisted extraction (UAE) of phytochemicals, antioxidant profiling, and safety of Hibiscus rosa-sinensis powder and methanolic extracts in an animal model. Antioxidant samples were prepared in a ratio of 1:20, with the results showing the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activity in the methanol extract at 86.45% and 91.12%. Functional groups were examined using a Bruker Alpha FTIR spectrometer, and the analysis revealed the presence of O–H, –COOH, C≡N, C=O, and C–H functional groups. Gas Chromatography–Mass Spectrometry (GC–MS) profiling was done using a GC/MSD thermal desorption system, and results showed major compounds with the highest percentage are 1,2-Cyclohexanedicarboxylic acid, bis (2-ethylhexyl) ester 2-[3-Chlorophenoxy] propionamide (25.29%), and 1,2-Cyclohexanedicarboxylic acid, bis (2-ethylhexyl) ester, 2-[3-Chlorophenoxy] propionamide (17.77%), respectively. For the sub-acute toxicity study, 25 male Sprague Dawley rats were distributed in five groups and supplemented with the following doses of flower powder and extracts (Control: Placebo, Hibiscus rosa-sinensis powder diet 1 (HRPD1): 500 mg/kg BW powder, HRPD2: 1000 mg/kg BW powder, Hibiscus rosa-sinensis extract diet 1 (HRED1): 100 mg/kg BW extract, and HRED2: 200 mg/kg extract) for 28 days. The safety evaluation showed no adverse impact and toxic signs in animals, as the values of hematological and biochemical parameters remained in normal ranges, with no hepato-renal changes noticed in histopathological examination. In a nutshell, Hibiscus rosa-sinensis exhibited significant bioactive compounds and functional groups, paving the way for its application in pharmaceuticals and nutraceuticals. Moreover, the powder and extracts proved safe at this dose; however, further preclinical trials are required at a high dose to validate their safety and efficacy in clinical trials.