Antioxidant, Anti-inflammatory Activities and Polyphenol Profile of Rhamnus prinoides

Abstract

Rhamnus prinoides L’Herit (R. prinoides) has long been widely consumed as folk medicine in Kenya and other Africa countries. Previous studies indicated that polyphenols were abundant in genus Rhamnus and exhibited outstanding antioxidant and anti-inflammatory activities. However, there are very few studies on such pharmacological activities and the polyphenol profile of this plant up to now. In the present study, the antioxidant activities of the crude R. prinoides extracts (CRE) and the semi-purified R. prinoides extracts (SPRE) of polyphenol enriched fractions were evaluated to show the strong radical scavenging effects against 1,1-diphenyl-2- picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) (0.510 ± 0.046 and 0.204 ± 0.005, mg/mL), and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) (0.596 ± 0.005 and 0.096 ± 0.004, mg/mL), respectively. Later, the SPRE with higher contents of polyphenols and flavonoids displayed obvious anti-inflammatory activities through reducing the NO production at the dosage of 11.11 − 100 μg/mL, and the COX-2 inhibitory activity with an IC50 value at 20.61 ± 0.13 μg/mL. Meanwhile, the HPLC-UV/ESI-MS/MS analysis of polyphenol profile of R. prinoides revealed that flavonoids and their glycosides were the major ingredients, and potentially responsible for its strong antioxidant and anti-inflammatory activities. For the first time, the present study comprehensively demonstrated the chemical profile of R. prinoides, as well as noteworthy antioxidant and anti-inflammatory activities, which confirmed that R. prinoides is a good natural source of polyphenols and flavonoids, and provided valuable information on this medicinal plant as folk medicine and with good potential for future healthcare practice.

Antioxidant and Antiproliferative Potentials of Ficus glumosa and Its Bioactive Polyphenol Metabolites

“…Compound 2 displayed a precursor molecular ion [M-H] − at m/z 153, and the loss of carboxyl group (44 Da) between the major fragment ions at m/z 153 and m/z 109 an indication of decarboxylation. The deprotonation of a molecule ion at m/z 153 led to the tentative identification of compound 2 as protocatechuic acid [ 45 ].…”

Phytochemistry, Ethnomedicinal Uses and Pharmacological Properties of Rhamnus prinoides: A Review

“…Semi purified ethanolic stem and stem bark extracts of R.prinoides with higher contents of polyphenols and flavonoids displayed anti-inflammatory activity through reducing the Nitric Oxide production at the dosage of 11.11-100 μg/mL and the COX-2 inhibitory activity with an IC50 value at 20.61 ±0.13 μg/mL (Chen et al, 2020).…”

“…The decoction of the leaves is recommended as remedy for treatment of variety of diseases such as back pain, malaria, pneumonia, sexually transmitted disease, skin infections, wounds, blood purifiers, water borne diseases and as ethnoveterinary medicine (Berhanu, 2014;Enyew et al, 2014;Fratkin, 1996;Megersa et al, 2013;Muthee et al, 2011;Njoroge & Bussmann, 2006;Prozesky et al, 2001;Sobiecki, 2002).The leaves are maily used in traditional medicine followed by roots (Araya et al, 2015;Diallo et al, 2002;Giday et al, 2010;Seid & Aydagnehum, 2013). Various class of secondary metabolites such as flavonoids, alkaloids, tannins, terpenoids, saponins, steroids and anthraquinones have been reported from the genus of which polyphenols were abundant withtremendous antioxidant and antiinflammatory activities (Chen et al, 2020). The plant also serve as an important hopping agent, making traditional alcoholic beverages like tella and tej (in Ethiopia), animal feed, medicine, nectar for bees, soil conservation, ornamental, shade and dyes in textiles.…”

Traditional Medicinal Uses, Phytochemicals, and Pharmacological Activities of Genus Rhamnus: A review

“…Apigenin (40) and Kaempferol (33) exhibited anti-inflammatory activity with IC50 values of 10.14 and 9.27 μg/mL, respectively (74). Chen et al, (2020) evaluated anti-inflammatory activity of 60% ethanol stem and stem bark semipurified extracts of R.prinoides using cyclooxygenase (COX-2) inhibition assay, with aspirin as the positive control. The semi-purified extract exhibited activity with IC50 value of 20.6 μg/mL, which was weak activity compared to IC50 value of 6.33 μg/mL exhibited by ascorbic acid (116).…”

“…Chen et al, (2020) evaluated anti-inflammatory activity of 60% ethanol stem and stem bark semipurified extracts of R.prinoides using cyclooxygenase (COX-2) inhibition assay, with aspirin as the positive control. The semi-purified extract exhibited activity with IC50 value of 20.6 μg/mL, which was weak activity compared to IC50 value of 6.33 μg/mL exhibited by ascorbic acid (116). Molla et al, (2016) evaluated antibacterial activities of methanol and chloroform solvent fractions of R.prinoides crude leaves extract against S. aureus, S. pyogen, S. pneumoniae, and S. typhi using agar well diffusion methods with ampicillin and ciprofloxacin as positive controls.…”