Photo-assisted bio-fabrication of silver nanoparticles using Annona muricata leaf extract: exploring the antioxidant, anti-diabetic, antimicrobial, and cytotoxic activities.

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 (IC50 = 51.80 µg/ml), ABTS (IC50 = 30.78 µg/ml), α-amylase (IC50 = 0.90 µg/ml) and α-glucosidase (IC50 = 3.32 µg/ml). The particles exhibited a dose-dependent inhibition of Fe2+-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.

Chemopreventive and anti-leukemic effects of ethanol extracts of Moringa oleifera leaves on wistar rats bearing benzene induced leukemia.

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.

Effects of extracts of the leaves of Brysocarpus coccineus on rat liver mitochondrial membrane permeability transition (MMPT) pore.

OBJECTIVE: To examine the influence or the effect of the extracts of Brysocarpus coccineus leaves on the mitochondrial membrane permeability transition (MMPT) pore opening in rats with a view to establishing if any bioactive constituent of the plant could become useful in the chemotherapy of cancer. MATERIALS AND METHODS: The effects of extracts of the leaves of Brysocarpus coccineus, a medicinal plant with anti-tumour, anti-inflammatory and analgesic properties, were assessed on rat liver mitochondrial membrane permeability transition (MMPT) pore in the presence and absence of calcium in vitro and in vivo. RESULTS: The results obtained show that calcium ions induced the opening of MMPT pore significantly (P < 0.05) in rat liver mitochondria, while spermine inhibited calcium-induced opening of pore, indicating that the mitochondria were intact ab initio. The results further revealed the inhibitory effects of different concentrations (200, 600, 1000, 1400, and 1800 microg/ml) of the various extracts of the leaves compared with spermine. Specifically, the data revealed that chloroform and ethylacetate extracts reversed calcium-induced opening of MMPT pore in a concentration-dependent manner (74%, 79%, 85%, 86%, 87%) for the chloroform extract and (36%, 37%, 59%, 71% and 83%) for the ethylacetate extract, respectively. On the contrary, pre-incubation of normal healthy mitochondria with the extracts in the absence of calcium resulted in the induction of the MMPT pore opening to varying degrees by these concentrations of the extracts. The chloroform extract induced pore opening in a concentration-dependent manner in the order 2.4, 2.4, 2.5, 2.6 and 3.0 folds while the ethylacetate extracts induced the opening of the pore by 1.1, 1.2, 1.3, 1.3 and 1.4 folds between 200-1800 microg/ml, respectively. The results obtained using rats orally exposed to various doses of methanol extract of the leaves of B. coccineus for fourteen days showed that there was significant (p < 0.05) induction of mitochondrial membrane permeability transition pore opening in the absence of calcium in a dose-dependent manner. Maximum induction of 26-fold was obtained at 200 mg/kgbwt while the least dose (50 mg/kgbwt) gave 17 fold induction. CONCLUSION: The ability of the extracts of B. coccineus to induce MMPT pore opening in the absence of calcium in vitro and in vivo suggest that the leaves of the plant contain certain bioactive substances capable of inducing MMPT opening either in the original form or as formed biotrans derivative with eventual release of apoptotic proteins which may lead to apoptosis. The property of the extracts could be exploited for cancer chemotherapy when increased rate of apoptosis is required.