Fraction-Dependent Redox Modulation by Tapinanthus globiferus Leaf Extracts Parasitizing Psidum guajava in Drosophila melanogaster

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.