Modulatory effects of moringa (Moringa oleifera L.) leaves infested with African mistletoe (Tapinanthus bangwensis L.) on the antioxidant, antidiabetic, and neurochemical indices in high sucrose diet-induced diabetic-like phenotype in fruit flies (Drosophila melanogaster M.)

Host-parasite relationship modulates the effect of African mistletoe leaves on the cholinergic, monoaminergic and carbohydrate hydrolyzing enzymes in fruit fly

OBJECTIVES

Mistletoe infests common plant trees of great medicinal values such as Moringa and Almond. According to folklore, mistletoe leaves have been found to have application as food and medicine in the alleviation of various degenerative diseases. Host-parasite relationship may possibly influence the phytochemical and biological activities of mistletoe leaves. Hence, we examined the polyphenol contents, antioxidant properties, α-amylase, α-glucosidase, acetylcholinesterase (AChE) and monoamine oxidase (MAO) inhibitory activities of African mistletoe leaves obtained from Moringa and Almond host plants in fruit fly in vitro.

METHODS

The phenolic constituents of the leaves were evaluated using HPLC system. The antioxidant activities were determined through the ABTS, DPPH and OH free radicals scavenging properties, ferric (Fe3+) and malondialdehyde (MDA) reducing abilities and Fe2+ chelation. The inhibitory effects of the leaves aqueous extracts on α-amylase, α-glucosidase, AChE and MAO activities were also assessed.

RESULTS

The HPLC characterization of the leaves revealed that host plants caused marked variation in their phenolic composition, however, Almond mistletoe leaves had significantly (p<0.05) greater amounts of phenolic constituents. Both Moringa and Almond mistletoe leaves reduced Fe3+ and MDA levels, scavenged free radicals, chelated Fe2+ and inhibited α-amylase, α-glucosidase, AChE and MAO activities with the Almond mistletoe leaves having significantly (p<0.05) higher antioxidant properties and enzyme inhibitory activities.

CONCLUSIONS

This present study indicated that host plants could positively modulate the phenolic profile of mistletoe leaves and this probably brought about the vivid noticeable changes in their antioxidant abilities, cholinergic, monoaminergic and carbohydrate hydrolyzing enzymes inhibitory activities.

Ameliorative effect of bayberry leaves proanthocyanidins on high sugar diet induced Drosophila melanogaster

Bayberry leaves proanthocyanidins (BLPs) were distributed in natural plant food, considered to have the potential for metabolic syndrome. In this study, we raised Drosophila melanogaster on high sugar diet (HSD) from the egg stage to induce hyperglycemia, and the ameliorative effect of BLPs was assessed based on this model. Phenotypical, biochemical, and molecular analyses related to diabetes mellitus pathogenesis were measured. Flies exposed to BLPs were found to suppress the HSD-induced high glucose and high triglycerides levels. Moreover, BLPs showed an inhibitory effect on carbohydrate digestive enzymes (α-amylase and α-glucosidase) activity and mRNA expression, exhibiting the potential for carbohydrate digestion retardation. Transcriptional levels of key genes associated with glycolipid metabolism were further evaluated, including dilp, InR, and downstream dAKT-dFOXO-PEPCK, together with E78, SREBP, FAS, and LSD genes, were all downregulated after BLPs-exposure, suggesting the ameliorative effect of BLPs on dysbiosis associated with the insulin signaling pathway. This study provided a new functional compound, which is beneficial to further antidiabetic therapy studies.

Novel ketogenic diet formulation improves sucrose-induced insulin resistance in canton strain Drosophila melanogaster

This study investigates the antidiabetic effect of a ketogenic diet (KD) on sucrose-induced insulin resistance in the fruit fly model. The fruit flies were divided and grouped into four: Group A, B, C, and D, representing the control, high-sucrose diet (HSD), KD, and HSD + KD, respectively. The administration of the various treatments to the groups proceeded for 7 days. The flies were thereafter immobilized, homogenized, and the homogenates used for biochemical parameters determination. This includes glucose concentration, antioxidant status, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, total cholesterol (TC), triglycerides (TG), and protein concentration. There was a significant increase (p < .05) in weight gain, glucose concentration, TG, HMG-CoA reductase activity, TC, and lipid peroxidation status of the HSD group compared with the control and KD groups. The antioxidant enzymes measured (superoxide dismutase, catalase, and reduced glutathione) and protein concentrations were repressed significantly (p < .05) in the HD groups but significantly elevated (p < .05) in the KD, HSD + KD, and the control groups. The KD improved biochemical parameters altered during the onset of sucrose-induced insulin resistance. With further research on this, KD may emerge as the much-awaited treatment option for diabetes mellitus type 2 (T2DM) with almost reduced toxicity concerns. PRACTICAL APPLICATIONS: Novel KD are sources of dietary phytocompounds with proven antioxidant activities. The antidiabetic activity of the KD was investigated. The results showed that the KD proves to serve as a better effective antidiabetic option in Drosophila melanogaster. The observed results could provide the potential application of the KD as an alternative therapy for diabetes management.

Phenolic constituents and inhibitory effects of the leaf of Rauvolfia vomitoria Afzel on free radicals, cholinergic and monoaminergic enzymes in rat's brain in vitro

OBJECTIVES

Rauvolfia vomitoria is a medicinal plant used traditionally in Africa in the management of several human diseases including psychosis. However, there is inadequate scientific information on the potency of the phenolic constituents of R. vomitoria leaf in the management of neurodegeneration. Therefore, this study characterized the phenolic constituents and investigated the effects of aqueous and methanolic extracts of R. vomitoria leaf on free radicals, Fe²⁺-induced lipid peroxidation, and critical enzymes linked to neurodegeneration in rat's brain in vitro.

METHODS

The polyphenols were evaluated by characterizing phenolic constituents using high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The antioxidant properties were assessed through the extracts ability to reduce Fe³⁺ to Fe²⁺; inhibit ABTS, DPPH, and OH radicals and Fe²⁺-induced lipid peroxidation. The effects of the extracts on AChE and MAO were also evaluated.

RESULTS

The phenolic characterization of R. vomitoria leaf revealed that there were more flavonoids present. Both aqueous and methanolic extracts of R. vomitoria leaf had inhibitory effects with the methanolic extract having higher significant (p≤0.05) free radicals scavenging ability coupled with inhibition of monoamine oxidases. However, there was no significant (p≤0.05) difference obtained in the inhibition of lipid peroxidation and cholinesterases.

CONCLUSION

This study suggests that the rich phenolic constituents of R. vomitoria leaf might contribute to the observed antioxidative and neuroprotective effects. The methanolic extract was more potent than the aqueous extract; therefore, extraction of R. vomitoria leaf with methanol could offer better health-promoting effects in neurodegenerative condition.