Frontiers in Natural Product Chemistry is a book series devoted to publishing monographs that highlight important advances in natural product chemistry. The series covers all aspects of research in the chemistry and biochemistry of naturally occurring compounds, including research on natural substances derived from plants, microbes and animals. Reviews of structure elucidation, biological activity, organic and experimental synthesis of natural products as well as developments of new methods are also included in the series.Volume nine of the series brings together 7 reviews on a variety of natural products and sources along with a chapter on the basics of investigating antioxidant activity.Propolis and its key chemical constituents: a promising natural product in therapeutic applicationsInvestigation of the effects of using omega-3 fatty acids on egg quality in functional egg productionQuercetin, a flavonoid with remarkable anticancer activitySwertiamarin for the treatment of metabolic syndromeoverview of traditional uses, phytochemistry and pharmacology of Peganum harmala l.Investigation of measurement methods of antioxidant activity and involved mechanismsRecent progress on natural and synthetic flavanone and its derivativesRole of virgin coconut oil as a multiple health promoting functional oil