Qualitative study of structure-activity relationship of compounds derived from Piper against Moniliophthora roreri

Cocoa is one of the primary species of the peasant agroforestry system of many regions in Colombia and is considered one of the most economically projected crops, given its added value, its high demand for various industries that can be grown along with other species of nutritional importance. Production yields in our country are very low, due to multiple factors among which include diseases caused by various types of phytopathogenic fungi (De Souza et al., 2018; Guest, 2007). The Piper genus is one of the most representative of the family and is characterized by the content of various metabolites with antifungal activity among which phenylpropanes, amides, benzoic acid derivatives and flavonoids, among others. Given the interest of our research team in this field, this proposal aims to determine the potential of species belonging to the genus Piper, for the control of phytopathogenic fungi associated with cocoa cultivation (Xu et al., 2011). Therefore, it is of great interest to find affected and safe phytosanitary agents for the control of phytopathogenic fungi associated with cocoa cultivation in order to minimize losses and increase production yields. In the research studies of structure-activity relationship found from the isolated constituents of Piper pesaresanum with potential application in the control of phytopathogenic fungi associated cocoa.

The methodology included the biodirected chemical study on the aerial part of P. pesaresanum to isolate and identify bioactive constituents. The synthesis of derivatives was then carried out from the bioactive constituents and the isolated and synthesized compounds were determined antifungal activity by the technique of inhibiting mycelial growth against Moniliophthora roreri.

The results allowed to establish that for the benzoic acid derivatives the presence of pre-substituted substituents and the carboxyl group in the aromatic ring are necessary for the antifungal activity. The activity is significantly increased when the cyclic compounds of the chromene and 4-chromanone type are synthesized.