Abstract:
Moringa and almond are common trees with mistletoe infestations which may cause principal changes in the phytochemical profiling and biological activities of the infested host plants. However, there still exists dearth of information underlying the possible influence of mistletoe infestation on the phytoconstituents and biological activities of host plants, particularly, moringa and almond leaves. Hence, this study sought to investigate the phytochemistry and antidiabetic activities of mistletoe infested and non-infested moringa and almond leaves in sucrose-induced diabetic-like phenotypes in Drosophila melanogaster model. Phytochemical screening, HPLC-DAD quantification of phenolics, antioxidant properties and inhibition of α-amylase and α-glucosidase were determined in vitro. Thereafter, the effects of diets supplemented with infested and non-infested moringa and almond leaves in normal and diabetic-like flies were evaluated on glucose, trehalose, triglyceride and insulin-like peptide levels, activities of carbohydrate hydrolyzing enzymes, antioxidant status and gene expression levels of Drosophila insulin-like peptide-2 (dILP-2), superoxide dismutase (SOD) and heat shock protein-70 (HSP-70). The mistletoe infested leaves had significantly (p < 0.05) higher polyphenol constituents (catechin, protocatechuic acid, kaempferol, myricetin, chlorogenic acid, P-hydroxybenzoic acid, quercetin and isorhamnetin), antioxidant (ABTS, DPPH, OH and Fe2+ chelation) and enzyme (α-amylase) inhibitory activities in vitro when compared with non-infested leaves. High sucrose diet (HSD) fed flies had significantly (p < 0.05) elevated levels of glucose (23.45 mmol/L), trehalose (51.53 mmol/L), insulin-like peptides (15.48 nLU/mL) and triglycerides (36.75 mmol/L), increased oxidative (TBARS, 0.46 mmol/mg protein and GST, 0.03 μmol/min/mg protein) and enzyme (α-amylase, 0.47 μmol/mg protein) activities. There were upregulation of dILP-2 and HSP-70 mRNA transcript levels and downregulation of SOD gene. However, treatment with the moringa and almond mistletoe infested and non-infested moringa and almond leaves significantly (p < 0.05) reduced the negative alterations caused by HSD. The improved antioxidative and hypoglycemic activities of the mistletoe infested moringa and almond leaves could be related to their increased polyphenol composition when compared with the non-infested moringa and almond leaves. Hence, it is opined that infestation of moringa and almond trees with mistletoe resulted in increased production of phytoconstituents with consequent enhanced antidiabetic activities of the leaves.
