In vitro, fluorescence-quenching and computational studies on the interaction between lipoxygenase and 5-hydroxy-3′,4′,7-trimethoxyflavone fromLippia nodifloraL

Studies on the influence of natural resource utilization by humans on foraging behavior of honey bees at rural ecosystems

Human utilization of natural resources acts as a main driver in altering the ecosystem service and functions. Apart from indirect influence, these human activities also tempt for the behavioral shift in insects especially in honey bees. The foraging behavior of honey bees from the natural floral resources to the man-made food sources eventually degrade the ecosystem's services and cause declining of the honey bee population. Understanding this foraging behavior of bees could help in opting for viable conservation measures for honey bees. In order to understand the influence of human utilization of natural resources on the foraging behavior of bees and its negative impacts on the bee population, the study was carried out in the sites where humans collect palm sap. Palm sap collectors used different containers (mud pots and pet bottles) to collect the palm sap from Borassus flabellifer. The number of containers per tree, volume of palm sap per container/tree, bee visiting frequency, and bee mortality per container/tree were measured at different ecosystems. Palm saps were collected freshly and volatile compounds of samples were identified using FT-IR and GC-MS analysis. The identified volatile compounds were used to study the interaction between volatile compounds and odorant-binding proteins (OBPs) of honey bees for understanding the foraging behavior of bees using in silico approach. Our results clearly showed that bee visitation frequency was directly correlated (0.94) with bee mortality in palm sap in different study sites. The average number of bee mortality was recorded as 491.2 ± 23.48 bees per container/tree/day. GC-MS analyses revealed the presence of 35 volatile compounds in collected palm sap from different study sites. Furthermore, molecular docking studies were performed for all 35 palm volatile compounds OBPs of honey bees to analyze their binding affinities. Docking studies showed that 1-methylbutylmandelate and 6-(hydroxymethyl)-1,4,4-trimethylbicyclo [3.1.0] hexan-2-ol have high binding affinity with OBP residues of bees. These volatile compounds might act as an attractant for bee populations for their foraging behavior. Based on this study, we conclude that human utilization of palm sap has created new ecological niches which highly alters the foraging behavior of bees and results in declining bee populations.

Cellular antioxidant activity and in vitro inhibition of α-glucosidase, α-amylase and pancreatic lipase of oregano polyphenols under simulated gastrointestinal digestion

Different oregano species have been traditionally used as infusions in folk medicine. Oregano medicinal properties, such as antioxidant and anti-inflammatory, have been partially attributed to its polyphenolic content. However, information regarding bioaccessibility of oregano polyphenols is limited. Cell-based antioxidant activity, and in vitro hypoglycemic, and hypolipidemic properties of polyphenolic extracts from three species of oregano species, namely, Hedeoma patens (HP), Lippia graveolens (LG) and Lippia palmeri (LP), subjected to simulated gastrointestinal digestion were evaluated. LC-TOF-MS analysis of HP, LG and LP allowed the identification of 9 flavonoids and 6 hydroxycinnamic acid derivatives with nutraceutical significance. Oregano polyphenolic extracts and digests from HP, LG, and LP exhibited cellular antioxidant capacity, hypoglycemic and hypolipidemic properties. Altogether, our results suggest that HP, LG and LP polyphenols exhibit potential for use as hypoglycemic, hypolipidemic, and antioxidant agents.