Evaluation of the chemical constituents,antioxidant and enzyme inhibitory activities of six Yemeni green coffee beans varieties

Coffee arabica L.is an economical crop cultivated in many countries including Yemen.The present study evaluated the phytochemical contents of the methanolic extracts,prepared by maceration,of six Yemeni green coffee beans varieties namely Esmaeli,Hamadi,Harazi,Mattari,Odaini and Yafei.Antioxidant(phosphomolybdenum,antiradical,reducing power and ferrous chelating),and enzyme inhibition activity of the extracts against acetylcholinesterase butyrylcholinesterase,tyrosinase,α-glucosidase,andα-amylase were also studied.Quantification of total phenols revealed that all green beans varieties were richer in their total polyphenolic(63.77-110.98 mg gallic acid equivalent per g of extract)content than their flavonoids one(2.86-5.57 mg rutin equivalent per g of extract).HPLC-MS/MS analysis of 30 selected bioactive compounds showed that all varieties had the same types of phytoconstituents with differences in their relative abundance.Caffeine(1613.89-2466.38μg/g)followed by 5-caffeoylquinic acid(1017.63-1313.39μg/g)were the dominant compounds in all varieties with caffeine more abundant in Esmaeli variety while 5-caffeoylquinic acid in Odaini variety.All varieties displayed a pronounced antioxidant property in all the in vitro assays with Odaini variety significantly(p<0.05)exerted the highest anti-DPPH radicals(253.96 mg Trolox equivalent(TE)/g),metal chelating(19.73 mg Disodium edetate equivalents/g),Cu^(2+)(441.11 mg TE/g)and Fe3+(221.04 mg TE/g)reducing activities.Furthermore,the majority of green coffee beans varieties showed comparable enzyme inhibition property with highest activity recorded against tyrosinase(39.35-46.96 mg kojic acid equivalents/g)and acetylcholinesterase(1.80-2.17 mg galanthamine equivalents/g)enzymes.In conclusion,all Yemeni green coffee beans varieties have proven to be rich source of biochemicals with beneficial impact on human health and could be of significant applications in food,pharmaceutical and cosmetics industry.

Characteristics of novel Ti-10Mo-xCu alloy by powder metallurgy for potential biomedical implant applications

When biomaterials are implanted in the human body,the surfaces of the implants become favorable sites for microbial adhesion and biofilm formation,causing peri-implant infection which frequently results in the failure of prosthetics and revision surgery.Ti-Mo alloy is one of the commonly used implant materials for load-bearing bone replacement,and the prevention of infection of Ti-Mo implants is therefore crucial.In this study,bacterial inhibitory copper(Cu)was added to Ti-Mo matrix to develop a novel Ti-Mo-Cu alloy with bacterial inhibitory property.The effects of Cu content on microstructure,tensile properties,cytocompatibility,and bacterial inhibitory ability of Ti-Mo-Cu alloy were systematically investigated.Results revealed that Ti-10Mo-1Cu alloy consisted ofαandβphases,while there were a few Ti2Cu intermetallic compounds existed for Ti-10Mo-3Cu and Ti-10Mo-5Cu alloys,in addition toαandβphases.The tensile strength of Ti-10Mo-xCu alloy increased with Cu content while elongation decreased.Ti-10Mo-3Cu alloy exhibited an optimal tensile strength of 1098.1 MPa and elongation of 5.2%.Cytocompatibility study indicated that none of the Ti-10Mo-xCu alloys had a negative effect on MC3T3-E1 cell proliferation.Bacterial inhibitory rates against S.aureus and E.coli increased with the increase in Cu content of Ti-10Mo-xCu alloy,within the ranges of 20-60%and 15-50%,respectively.Taken together,this study suggests that Ti-10Mo-3Cu alloy with high strength,acceptable elongation,excellent cytocompatibility,and the bacterial inhibitory property is a promising candidate for biomedical implant applications.