A new indole alkaloid, 12-hydroxy-N-acetyl-21(N)-dehydroplumeran-18-oic acid (13), and 11 known indole alkaloids: 3,4,5,6-tetradehydro-β-yohimbine (3), 19(E)-hunteracine (4), b-yohimbine (5), yohimbine (6), 19,20-dehydro-17-a-yohimbine (7), uleine (10), 20-epi-dasycarpidone (11), olivacine (8), 20-epi-N-nor-dasycarpidone (14), N-demethyluleine (15) and 20(E)-nor-subincanadine E (12) and a boonein d-lactone 9, ursolic acid (1) and 1D,1O-methyl-chiro-inositol (2) were isolated from the EtOH extracts of different parts of Aspidosperma ulei Markgr. (Apocynaceae). Identification and structural elucidation were based on IR, MS, ¹H- and ¹³C-NMR spectral data and comparison to literature data. The antiplasmodial and antimalarial activity of 1, 5, 6, 8, 10 and 15 has been previously evaluated and 1 and 10 have important in vitro and in vivo antimalarial properties according to patent and/or scientific literature. With the aim of discovering new antiplasmodial indole alkaloids, 3, 4, 11, 12 and 13 were evaluated for in vitro inhibition against the multi-drug resistant K1 strain of the human malaria parasite Plasmodium falciparum. IC₅₀ values of 14.0 (39.9), 4.5 (16.7) and 14.5 (54.3) mg/mL (mM) were determined for 3, 11 and 12, respectively. Inhibitory activity of 3, 4, 11, 12 and 13 was evaluated against NIH3T3 murine fibroblasts. None of these compounds exhibited toxicity to fibroblasts (IC₅₀ > 50 mg/mL). Of the five compounds screened for in vitro antiplasmodial activity, only 11 was active.

The present study reports the identification of two new staurosporine derivatives, 2-hydroxy-7-oxostaurosporine (1) and 3-hydroxy-7-oxostaurosporine (2), obtained from mid-polar fractions of an aqueous methanol extract of the tunicate Eudistoma vannamei, endemic to the northeast coast of Brazil. The mixture of 1 and 2 displayed IC₅₀ values in the nM range and was up to 14 times more cytotoxic than staurosporine across a panel of tumor cell lines, as evaluated using the MTT assay.

The phytochemical analysis of the ethanol extract trunk bark of Amburana cearensis allowed the isolation and identification of twelve constituents: coumarin, sucrose, two phenol acids (vanillic acid and protocatechuic acid), five flavonoids (afrormosin, isokaempferide, kaempferol, quercetin and 4'-methoxy-fisetin), a phenol glucoside (amburoside A) and a mixture of glucosilated b-sitosterol and stigmasterol. Their structures were elucidated by spectroscopic methods such as IR, MS, ¹H and 13C NMR, including uni and bidimensional techniques, in addition to comparison with literature data

Violacein is an indole compound, produced by Chromobacterium violaceum, a bacteria present in tropical and subtropical areas. Among its numerous biological activities, its antimicrobial potential stands out. This study aims to determine the antimicrobial activity of VIO on S. aureus in planktonic culture and biofilms. VIO showed excellent antimicrobial activity in inhibiting and killing S. aureus in planktonic cultures and biofilm formation. The minimum bactericidal concentration (5 μg/mL) of VIO caused the death of S. aureus after 3–4 h of exposure and the minimum inhibitory concentration (1.25 μg/mL) of VIO inhibited bacterial growth within the first 8 h of contact. Biofilm formation was also strongly inhibited by VIO (1.25 μg/mL), in contrast to the higher resistance verified for S. aureus in mature biofilm (40 μg/mL). The high bacterial metabolic activity favored VIO activity; however, the good activity observed during phases of reduced metabolism indicates that VIO action involves more than one mechanism. Thus, VIO is a promising molecule for the development of an antimicrobial drug for the eradication of S. aureus infections.