Two new tryptophan derivatives from the seed kernels of Entada rheedei: Effects on cell viability and HIV infectivity

Abstract

Two new tryptophan derivatives, N-sulfonyl-L-tryptophan (tryptorheedei A) (1) and 3-(N-sulfonylindolyl)-D-lactic acid (tryptorheedei B) (2) together with the known 5-O-β-D-glucopyranosyl-2-hydroxyphenylacetic acid (3), 1-O-methylglucopyranoside, entadamide A, homogentisic acid and 3-O-β-D-glucopyranosyl-β-sitosterol, were isolated from the seed kernels of Entada rheedei (Mimosaceae). Their structures were established using 1D and 2D NMR spectroscopy, mass spectrometry and by comparison with spectroscopic data reported in the literature. Compounds 1 and 2 showed no toxicity to TZM and Human PBMC cells. Both compounds 1 and 2 were found to promote early infection events in HIV, likely by inhibiting the enzyme indolamine 2,3-dioxygenase (IDO) and preventing tryptophan depletion. Inhibition of IDO acutely in HIV infection inhibits viral replication, but chronic activation of IDO leads to immune impairment in AIDS. IDO is also the gatekeeper enzyme for kynurenine metabolism, a pathway involved in serotonin and melatonin biosynthesis and the regulation of glutamate and dopamine levels in the brain. Therefore inhibition of IDO might explain both the reported medicinal and neuropsychiatric effects of E. rheedei.

Oxidative Stress during HIV Infection: Mechanisms and Consequences

“…Furthermore, IDO activity causes even more imbalance in the T-cell subsets by increasing the proportion of T-regulatory [193] and decreasing the proportion of T-helper 17 cells [194]. In chronically infected hosts, the dysregulated activation/alterations in the immune regulatory mechanisms involving IDO lead to a compromised antiviral response and enhancement of viral replication [195–197]. In short, chronic IDO activation leads to the immune impairment, whereas IDO inhibition represses viral replication.…”

Sappanin-type homoisoflavonoids from Sansevieria trifasciata Prain

“…Previous chemical studies on Sansevieria trifasciata led to the isolation of steroidal sapogenins namely 25S-ruscogenin and sansevierigenin (Gonzalez et al, 1972), pregnane glycosides (Mimaki et al, 1997), and steroidal saponins (Mimaki et al, 1996). As part of our program based on the phytochemical investigation of Cameroonian medicinal plants (Nzowa et al, 2013;Teponno et al, 2013a;Fouedjou et al, 2014;Ponou et al, 2014), we have examined the aerial parts of S. trifasciata growing in Cameroon and this work led to the isolation and structure elucidation of two new sappanin-type homoisoflavonoids. Homoisoflavonoids are a rather uncommon subclass of flavonoids rarely found in nature which contain one additional carbon atom.…”

Development and Validation of an GC-MS Method to Quantify Phytoconstituents by Using Entada pursaetha DC

“…Many other studies are also noted the phytochemical profile of the Entada species and the phytocompounds are corresponding the pharmacological activities like antimicrobial and antioxidants (Rahman et al, 2013;Nathan, 2017). Nzowa et al, (2013) have been reported the tryptophan derivatives in seed kernel of E. rheedii. The present results are also on par with above investigation that has been enumerated many pyridine and purine compounds in E. pursaetha plant part extract (Tables 1-2).…”