Quantitative Evaluation of Various Preparations and Extracts of the Male Contraceptive Justicia gendarussa and Identification of a New Aminobenzyl Derivative

Abstract

Abstract Justicia gendarussa is a medicinal plant found in different regions of Indonesia and used in decoctions by Papuan tribes to reduce male fertility. An enriched ethanolic extract of this plant has been used in the frame of clinical trials in Indonesia to evaluate its male contraceptive activity. Previous studies have indicated that the flavonoid gendarusin A may have a role in the male contraception properties of this plant. In addition, the level of aminobenzyl derivatives was lowered as a safety precaution. In order to obtain a comprehensive chemical profile of the methanolic plant extract, it was analysed by HPLC-PDA-ESI-MS and UHPLC-TOF-HRMS. The same method was also applied to profile extracts of the same plant material from different Indonesian regions, a water decoction used traditionally, and the enriched extract used in clinical trials. This allowed for the dereplication of all previously known flavonoids and newly reported amides, and permitted highlighting the presence of the potentially new aminobenzyl derivative. Targeted isolation of this new amide was performed using medium-pressure liquid chromatography. NMR and HRMS allowed for the establishment of the identity of the novel compound. The same procedure was used to obtain pure standards for quantitative studies. Quantitation of the major compounds was performed for different extracts using HPLC-UV. Significant differences were observed between the samples. Although gendarusin A was the main compound in all samples, it occurred in different amounts in the batches of dried material obtained from different Indonesian regions. The enriched extract contained mainly gendarusin A, as did the traditional decoction, but the level of the aminobenzyl derivatives was significantly lower.