Investigation On The Secondary Metabolites Of Two Endophytes From Medicinal Plants

Alternaria species,belonging to the Pleosporaceae family,more than 300,are widely distributed in many food and feed crops as well as in decaying organic material and soil as major plant pathogens.They are also common allergens in humans.It is well known as a source of many bioactive substances with vastly differing structures and various bioactivities.The secondary metabolites of Alternaria alternata isolated from Salvia miltiorrhiza were studied.Eleven compounds were purified,including seven alternariol derivatives(Aa-1–Aa-7),two terpenes(Aa-8,Aa-9),a fatty acid(Aa-10),and a derivative of benzene(Aa-11).Fusarium are widely distributed,among which some species are plant pathogens.The fungus rots on the crop and produces a lot of toxins that pollute the food and vegetables.Therefore,Fusarium proliferatum,isolated from green Chinese onion(Allium fistulosum),was cultivated using rice medinm and then its secondary metabolites were investigated.A total of 20 compounds were elucidated,including three sesquiterpene derivatives(F-1–F-3),two cyclopeptides(F-4,F-5),one sesterterpene(F-6),two indoleacetic acid derivatives(F-7,F-8),three sterides(F-9–F-11),four quinones(F-12–F-15),four benzene derivatives(F-16–F-19),and a glyceride(F-20).Compound F-1(3?-hydroxy-?-acorenol)is a new acorane sesquiterpene.The antibacterial activity aginst nine strains of bacteria(MRSA(methicillinresistant Staphylococcus aureus),S.aureus Newman WT,S.aureus Mu50,S.aureus RN4220,Clostridium perfringens,Micrococcus tetragenus,Bacillus subtilis,Bacillus megaterium and Escherichia coli)of 31 compounds was evaluated.Compounds F-12–F-15 exhibited moderate antibacterial activity.In conclusion,being focused on the regulatory of fermentation conditions of these strains,the isolation,structure elucidation,and antibacterial activity of the secondary metabolites from two endophytes,31 variety compounds were yielded.The results enriched the natural product database,which provided some basis for the development and utilization of microbial resources.