Antimycobacterial Activity and Alkaloid Prospection ofPsychotriaSpecies (Rubiaceae) from the Brazilian Atlantic Rainforest

Abstract

Ten Psychotria species were collected in two fragments of Atlantic Forest in Rio de Janeiro: Psychotria pubigera (P1A and B), P. ruelliifolia (P2), P. suterela (P3), P. stachyoides (P4), P. capitata (P5), P. glaziovii (P6), P. leiocarpa (P7), P. nuda (P8), P. racemosa (P9) and P. vellosiana (P10). Ethanol extracts of these species were evaluated for their antimycobacterial activity, in an attempt to find new antituberculosis agents. Psychotria pubigera (P1A), P. ruelliifolia (P2) and P. stachyoides (P4) were the most active against Mycobacterium. The anti-inflammatory potential of these extracts was also evaluated in vitro to learn if they inhibit nitric oxide (NO) production in macrophages and if they have free-radical scavenging properties, because inflammation is a severe problem caused by tuberculosis, especially when the infection is from M. bovis or M. tuberculosis. Psychotria suterela (P3), P. stachyoides (P4) and P. capitata (P5) were the most active in inhibiting macrophage NO production but they were not the most antioxidant species. This suggests that NO inhibitory activity is not due to the scavenging of NO generated but due to a specific inhibition of iNOS activity or expression. In addition, cytotoxicity was tested in the macrophages (the host cells of the Mycobacterium) and it was verified that the extracts selectively killed the bacteria and not the host cells. When analyzing antimycobacterial, cytotoxicity and NO inhibitory activities in combination, P. stachyoides (P4) was the most promising anti-TB extract tested. Further, indol alkaloids were detected in P. suterela and P. nuda, and 5,6-dihydro-β-carboline alkaloids in all of the species studied, with the highest amounts found in P. capitata and P. racemosa.

The GenusPsychotria: Phytochemistry, Chemotaxonomy, Ethnopharmacology and Biological Properties

“…Interestingly 5,6-dihydro-β-carboline alkaloids were found in all of the ten species evaluated, besides, indol alkaloids were also detected in P. nuda and P. suterela. 111 …”

“…76 From the leaves of the same species were isolated some other alkaloids like psychotrimine (17) and psychopentamine (18), which showed anti-bactericidal activity against resistant grampositive bacteria Bacillus subtilis and S. aureus. 77,117 In a study made by Moraes et al, 111 ten Psychotria species (P. pubigera, P. ruelliifolia, P. suterela, P. stachyoides, P. capitata, P. glaziovii, P. leiocarpa, P. nuda, P. racemosa and P. vellosiana) were evaluated for antimycobacterial activity, in an attempt to find new antituberculosis agents. From the evaluated extracts the species P. pubigera, P. ruelliifolia and P. stachyoides were the most active against Mycobacterium.…”

Nitric oxide production, inhibitory, antioxidant and antimycobacterial activities of the fruits extract and flavonoid content of Schinus terebinthifolius

“…The LDH release, which represents an indirect indication of cytotoxicity, was determined using a commercial kit (Raso et al, 2001;Moraes et al, 2011). The specific release was calculated as percentage of the controls: untreated macrophages and 1% Triton X-100 (Vetec Chem.)…”

“…Besides the anti-inflammatory activity, our group investigated the antimicrobial activity of natural products in order to contribute to the discovery of new anti-tuberculosis agents (Moraes et al, 2011). For this purpose, Schinus terebinthifolius methanol extract, fraction and apigenin (1) were also evaluated.…”

Chemical Constituents of Psychotria nemorosa Gardner and Antinociceptive Activity

“…It is commonly used in folk herbal medicine for regulating menstrual disturbance, fever, against microbial infections, anti-inflammatory, analgesic, anticonvulsant, anti-rheumatic and even as cardiovascular, mental and eating disorders. [10][11][12][13] Psychotria genus is a source of alkaloids, but other compounds like terpenes, flavonoids, tannins, coumarins and cyclotides (circular peptides) has also been isolated.…”