Bioguided isolation of N-malonyl-(+)-tryptophan from the fruit of Pithecellobium dulce (Roxb.) Benth. that showed high activity against Hymenolepis nana.

Pithecellobium dulce is distributed in America and Asia where is widely used in traditional medicine. This study describes the bioguided fractionation of the methanol extract (ME) obtained from the P. dulce fruit that showed in vitro activity against Hymenolepis nana; Artemia salina assay was used to determine toxicity; and the purified compound was computationally analysed to obtain its absorption-distribution-metabolism-excretion-and-toxicity properties (ADMET). The ME and its fractions were more active than praziquantel (PZQ), and the purified compound was characterized as N-malonyl-(+)-tryptophan (NMT). Parasites treated with NMT showed shorter paralysis and death times (5 and 7 min) than those treated with PZQ (15 and 30 min), both used at 20 mg/mL. Toxicity and ADMET prediction results supported the slight-hazardousness and efficacy of the assayed fractions/compound. This is the first report of the antiparasitary activity of both the P. dulce ME and NMT, showing their potential to treat human H. nana infections.

Chemical composition and biological activities of Helicteres vegae and Heliopsis sinaloensis.

CONTEXT: Helicteres vegae Cristóbal (Sterculiaceae) (Hv) and Heliopsis sinaloensis B.L. Turner (Asteraceae) (Hs) are endangered and poorly studied plant species; related plants have been used against chronic-degenerative and infectious diseases. Therefore, Hv and Hs could be sources of bioactive compounds against these illnesses. OBJECTIVE: To determine the chemical composition and biological activities (antioxidant, antimutagenic and antimicrobial) of Hv and Hs leaves (L) and stems (S). MATERIALS AND METHODS: Methanol extracts (ME) of each plant/tissue were evaluated for their phytochemicals; phenolics (HPLC-DAD-ESI-MS); antioxidant activity (AA) (0.125-4 mg/mL) (DPPH, ABTS, ORAC and ß-carotene discoloration); antimutagenicity (0.5 and 1 mg/plate) (Ames assay, tester strain Salmonella enterica serovar Typhimurium YG1024, 1-nitropyrene as mutagen); activity against human pathogens (1 mg/mL); and toxicity (0.01-2 mg/mL) (Artemia salina assay). RESULTS: All ME showed flavonoids and triterpenes/steroids. The ME-SHv had the highest content of total phenolics (TP) (2245.82 ± 21.45 mg GAE/100 g d.w.) and condensed tannins (603.71 ± 1.115 mg CE/100 g d.w.). The compounds identified were flavonoids (kaempferol 7-O-coumaroylhexoside, and two kaempferol 7-O-rhamnosylhexosides) and phenolics [rosmarinic acid, and 3'-O-(8″-Z-caffeoyl) rosmarinic acid]. The ME-LHs showed the highest content of flavonoids (357.88 mg RE/g d.w.) and phenolic acids (238.58 mg CAE/g d.w.) by HPLC. The ME-SHv showed the highest AA. All ME were strong antimutagens (63.3-85.7%). Only the Hs extracts were toxic (ME-LHs, LC50 = 94.9 ± 1.7 µg/mL; ME-SHs, LC50 = 89.03 ± 4.42 µg/mL). DISCUSSION AND CONCLUSIONS: Both Hv and Hs are potential sources of preventive and therapeutic agents against chronic-degenerative diseases.