Green synthesis of metal nanoparticles is reputed to have a robust range of biomedical applications. Silver nanoparticles (AgNPs) bio-fabricated using aqueous leaf extract of Annona muricata were characterized and evaluated for in-vitro antioxidant, lipid peroxidation inhibition, anti-diabetic and antimicrobial activities as well as cytotoxicity in human keratinocyte cells (HaCaT).The extract induced colour change of silver salt solution which absorbed at 420 nm and confirmed the formation of AgNPs. FTIR showed that free amide and hydroxyl groups were responsible for the synthesized nanoparticles. Both XRD and SAED confirmed the crystalline nature of the particles with face centered cubic (FCC) phase. The zeta potential revealed -27.2 mV potential and average distribution size of 35 nm. DLS indicated that the majority of the particles were 86.78 nm size and with a polydispersity index (PDI) of 0.329.AgNPs displayed strong activities against DPPH (IC 50 ¼ 51.80 μg/ml), ABTS (IC 50 ¼ 30.78 μg/ml), α-amylase (IC 50 ¼ 0.90 μg/ml) and α-glucosidase (IC 50 ¼ 3.32 μg/ml). The particles exhibited a dose-dependent inhibition of Fe 2þ -induced lipid peroxidation with effective antimicrobial activity against a battery of bacterial strains and cytotoxicity in HaCaT cell line. These findings revealed the potential biomedical applications of the particles and further work will be required to establish its molecular mechanism of action.

Synthesis of nanoparticles by biological methods using microorganisms, enzymes or plant extracts has been suggested as possible ecofriendly alternative to chemical and physical methods which involve the use of harmful reducing agents. In the current study, silver nanoparticles (AgNPs) were synthesized by green approach from methanolic leaf extract of Blighia sapida. The synthesized AgNPs were characterized by UV-visible (UV-vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). The antioxidant activity was evaluated using DPPH radical scavenging assay, determination of total reductive potential, total phenolics content (TPC) and total flavonoids content (TFC) of the synthesized AgNPs. SEM analysis revealed that the size of the synthesized silver nanoparticles ranged from 50-70 nm with maximum UV-vis absorbance at 413 nm. DPPH radical scavenging activity, reducing power, total phenolic and total flavonoid contents of the synthesized AgNPs increased in a dose dependent manner as compared to ascorbic acid the standard reference used. This result confirmed that Blighia sapida is a potential biomaterial for synthesizing AgNPs which can be exploited for its antioxidant activity.

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Pharmacological exploitation of natural compounds has continued to lead to development of non-synthetic and non-toxic anticancer agents that are promising at ameliorating the menace of neoplastic diseases such as leukemia. This study is an attempt to determine the chemopreventive and antileukemic activities of ethanol extracts of Moringa oleifera leaves on benzene induced leukemia bearing rats. Leukemia was induced by intravenous injection of 0.2 mL benzene solution 48 hourly for 4 weeks in appropriate rat groups. Ethanol extract of Moringa oleifera (EMO) leaves was administered at 0.2 mL of 100 mg/mL to respective treatment rat groups. A standard antileukemic drug (cyclophosphamide) was also used to treat appropriate rat groups. Clinical examination of liver and spleen with hematological parameters were employed to assess the leukemia burden following analysis of the rat blood samples on Sysmex KX-21N automated instrument. Leukemia induction reflected in severe anemia and a marked leukocytosis over the control/baseline group. Liver and spleen enlargements were also observed in group exposed to benzene carcinogen. The in vivo antioxidative potential of EMO was evaluated using Malondialdehyde (MDA) and reduced glutathione (GSH) levels. The liver MDA and GSH levels obtained in benzene induced leukemic rats treated with EMO compared favorably with those obtained in similar treatments with the standard drug (p< 0.05). The extract demonstrated chemopreventive and anti-leukemic activities as much as the standard anti-leukemic drug (p>0.05) by ameliorating the induced leukemic condition in the affected rat groups owing to its bioactive constituents. This study reveals that the extract might be an active, natural and non-toxic anticancer drug lead.