Aims: To evaluate anti-diabetic and liver enzymes activities of aqueous extracts of Moringa oleifera and Bridelia ferruginea leaves in alloxan induced diabetic albino rats. Study design: Diabetes was induced in three groups of rats, one group was not treated while two groups were treated orally with M. oleifera and B. ferruginea extracts at 200, 400 and 800 mg/kg body weight of rats twice for 1 week respectively. One group was not induced and received distilled water only. The anti-diabetic and liver enzymes activities were determined from blood glucose and transaminases activities of the rats.

The leaf-extract of Cymbopogon citratus was evaluated for nutritional and anti-nutritional compositions. The results revealed that the plant leaves contained appreciable amounts of phytochemicals (alkaloids, glucosides, phenols, saponins, flavonoids and tannins), proximate compositions (proteins, carbohydrates, fats, crude fibre, ash and moisture), vitamins (A, C, E, B1, B2 and B9) and trace elements (Fe, Zn, Mn, Cu, Na, K, Ca and Co) in varying degrees. These chemical compositions obtained may be responsible for the nutritional and therapeutic uses. The proximate, vitamin and mineral compositions obtained suggested that the leaves may serve as cheap sources of vitamin A, C, E, B1, B2 and B9 as well as other macro-and micro-nutrients, and could be incorporated into human diets to meet-up with their recommended daily dietary allowances. The content of flavonoids, vitamin A, C and E in the leaf extract also suggests possible anti-oxidant effects of the plant leaves.

In recent years a number of studies have brought attention to the role of positive selection during the evolution of antigenic escape by influenza strains. Particularly, the identification of positively selected sites within antigenic domains of viral surface proteins has been used to suggest that the evolution of viral–host receptor binding specificity is driven by selection. Here we show that, following the 1918 outbreak, the antigenic sites of the hemagglutinin (HA) viral surface protein and the stalk region of neuraminidase became substitution hotspots. The hotspots show similar patterns of nucleotide substitution bias at synonymous and nonsynonymous sites. Such bias imposes directionality in amino acid replacements that can influence signals of selection at antigenic sites. Our results suggest that the high accumulation of substitutions within the antigenic sites of HA can explain not only cases of antigenic escape by antigenic drift but also lead to occasional episodes of viral extinction.

Graphical abstract