MOLECULAR NETWORKS: AN ANALYSIS ON ANNOTATIONS AND DISCOVERY OF NEW ASSETS. To speed up the discovery of bioactive natural products (NP), chemists have sought advanced approaches in analytical and computational chemistry in attempt to organize and extract information from large data sets. In this sense, the molecular networks (MN) successfully organized enormous sets of mass spectrometry (MS) data together with samples metadata information in an intuitive visualization in the spectral similarity networks format. GNPS (Global Natural Products Social Molecular Networking), a free online platform for storing and processing MSn data, is a leading application of spectral matching with public databases aimed at the dereplication and discovery of new bioactive products through molecular networks. In this review, we address the concept of GNPS spectral similarity networks, as well as their complementary computational tools, benefits and limitations applied in NP studies associated with dereplication, chemical ecology, functional genetics and determination of biosynthetic pathways.

Senna spectabilis (syn Cassia spectabilis) is one of the most important species within the Fabaceae family, natively found in Central and South America, as well as parts of Asia and Africa. Due to the extensive geographical distribution, this fast-growing tree produces a wide variety of bioactive secondary metabolites, being of special interest for chemical and pharmacological studies. Phytochemical investigations have shown that S. spectabilis produces over 40 constituents from different biosynthetic pathways, including piperidine alkaloids, pentacyclic terpenoids and anthraquinones, displaying antiproliferative, antitumoral and antifungal activities. Moreover, studies have also been conducted to identify endophytic and rizhospheric microorganisms associated to S. spectabilis and their chemical composition, enabling further elucidation of cadinane sesquiterpenoids, cytochalasins, depsipeptides and dibenzopirones. This review aims to provide an updated summary of the main features of S. spectabilis, compiling all currently available information on the chemical and pharmacological composition of its parts and its associated microorganisms.