Fraction-Dependent Redox Modulation by Tapinanthus globiferus Leaf Extracts Parasitizing Psidum guajava in Drosophila melanogaster
Jane-Rose I. Oche
*
Department of Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, University of Jos, Nigeria.
Jonathan D. Dabak
Department of Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, University of Jos, Nigeria.
Titilayo O. Johnson
Department of Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, University of Jos, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Tapinanthus globiferus, a hemiparasitic mistletoe extensively used in African ethnomedicine, was evaluated for its redox-modulatory and cytotoxic properties using Drosophila melanogaster under non-stressed physiological conditions. Methanolic crude extract and solvent-partitioned fractions (butanol, methanol, ethyl acetate) from leaves parasitizing Psidium guajava were administered via diet supplementation (1.0 mg/10 g) for 10 days. Survival analysis revealed enhanced longevity in flies treated with the butanol (77%) and methanol (63.3%) fractions, while the crude extract significantly reduced survival (43.6%). Biochemical assays indicated pro-oxidant activity in the crude and ethyl acetate fractions, evidenced by elevated hydrogen peroxide and protein carbonyl levels (p ≤ 0.0001, p = 0.008), and antioxidant effects in the butanol and methanol fractions, marked by reduced malondialdehyde and nitric oxide levels (p < 0.05). Glutathione depletion was observed in the crude extract group (p = 0.002), while GST activity and total thiol levels remained unchanged. Gene expression analysis showed upregulation of CNC (Nrf2 homolog) by the methanol fraction (p = 0.05) and downregulation by the ethyl acetate fraction (p = 0.0006), with no significant change in SOD1 expression. The crude extract exhibited the highest cytotoxicity in MTT assays. These findings highlight the fraction-dependent redox behavior of T. globiferus, supporting the therapeutic potential of its butanol and methanol fractions while cautioning against the use of unrefined extracts due to potential pro-oxidant and cytotoxic effects.
Tapinanthus globiferus, a hemiparasitic mistletoe extensively used in African ethnomedicine, was evaluated for its redox-modulatory and cytotoxic properties using Drosophila melanogaster under non-stressed physiological conditions. Methanolic crude extract and solvent-partitioned fractions (butanol, methanol, ethyl acetate) from leaves parasitizing Psidium guajava were administered via diet supplementation (1.0 mg/10 g) for 10 days. Survival analysis revealed enhanced longevity in flies treated with the butanol (77%) and methanol (63.3%) fractions, while the crude extract significantly reduced survival (43.6%). Biochemical assays indicated pro-oxidant activity in the crude and ethyl acetate fractions, evidenced by elevated hydrogen peroxide and protein carbonyl levels (p ≤ 0.0001, p = 0.008), and antioxidant effects in the butanol and methanol fractions, marked by reduced malondialdehyde and nitric oxide levels (p < 0.05). Glutathione depletion was observed in the crude extract group (p = 0.002), while GST activity and total thiol levels remained unchanged. Gene expression analysis showed upregulation of CNC (Nrf2 homolog) by the methanol fraction (p = 0.05) and downregulation by the ethyl acetate fraction (p = 0.0006), with no significant change in SOD1 expression. The crude extract exhibited the highest cytotoxicity in MTT assays. These findings highlight the fraction-dependent redox behavior of T. globiferus, supporting the therapeutic potential of its butanol and methanol fractions while cautioning against the use of unrefined extracts due to potential pro-oxidant and cytotoxic effects.
Keywords: Tapinanthus globiferus, oxidative stress, antioxidant, pro-oxidant, Drosophila melanogaster, cytotoxicity, polyphenols