Pyrrolidinoindoline Alkaloids from Psychotria colorata 1

Journal of Natural Products, 2016

Phytochemical investigation of the bark of Guatteria f riesiana afforded 12 new aporphines (1-12), along with nine known alkaloids (13-21). The structures of the new alkaloids were determined on the basis of spectroscopic data interpretation. The cytotoxic activity of the isolated compounds against a small panel of tumor cell lines was assessed using the Alamar blue assay. Guatteria Ruiz & Pav., the largest genus in the plant family Annonaceae, comprises approximately 310 species, all distributed through neotropical regions. 1 In Brazil, 385 identified species are catalogued, with most occurring in the Amazonian domain. 1 Some of them are known for their medicinal properties, 2 as supported by previous investigations revealing bioactive compounds showing potential anticancer, 3-6 antimicrobial, 4,5,7-10 antioxidant, 7 and antiparasitic activities. Guatteria friesiana (W.A. Rodrigues) Erkens & Maas is known popularly as "envireira" or "envira", and previous phytochemical investigations have described the chemical constituents of its essential oil 6,9,13 as well as aporphine alkaloids found in its leaves and stem. 3, In a continuing search for bioactive compounds from Amazonian annonaceous plants, 12 new (1-12) and nine previously described (13-21) alkaloids were obtained in a systematic activity-guided investigation of the bark of G. f riesiana. Compound 1 was obtained as light yellow oil. Its molecular formula of C 20 H 19 NO 3 was determined from its HRESIMS (m/ z 322.1443 [M + H] + , calcd 322.1438) and 13 C NMR data. The IR, UV, and NMR spectra were similar to those reported for demethoxyguadiscine ( ). 8 Analysis of the NMR data (Tables and) for 1 and for 14 8 confirmed that these compounds are very similar, except for the presence of a methoxy group at C-3 (s, δ H 4.04). This was supported by the HMBC correlations of H-4 with C-3 and CH 3 O-3 (Tables and). Therefore, structure 1 (3-methoxy-demethoxyguadiscine) was established, as shown. Compound 2 was obtained as a light yellow oil. Its molecular formula was determined to be C 21 H 23 NO 3 from the 13 C NMR (Table ) and HRESIMS data (m/z 338.1749 [M + H] + , calcd 338.1756). Its IR, UV, and NMR spectra (Tables and) were similar to those of 1. The main differences in the NMR data were related to the absence of the methylenedioxy bridge signal at δ H 6.10 (s) present in 1, which was replaced by two resonances for methoxy groups for 2 at δ H 3.81 (s, CH 3 O-1)

Natural product communications

Neurochemical research, 1996

An ethnopharmacological survey showed that home remedies prepared with flowers and fruits of Psychotria colorata are used by Amazonian peasants as pain killers. Psychopharmacological in vivo evaluation of alkaloids obtained from leaves and flowers of this species showed a marked dose-dependent naloxone-reversible analgesic activity, therefore suggesting an opioid-like pharmacological profile. This paper reports an inhibitory effect of P. colorata flower alkaloids on [3H]naloxone binding in rat striata as well as a decrease in adenylate cyclase basal activity. The alkaloids did not affect [3H] GMP-PNP binding. These findings provide a neurochemical basis for the opioid-like activity previously detected in vivo and point to Psychotria alkaloids as a potential source of new bioactive opiate derivatives.

Biochemical Systematics and Ecology, 2001

S 0 3 0 5 -1 9 7 8 ( 0 1 ) 0 0 0 5 9 -X

Journal of the Brazilian Chemical Society, 2012

A continuidade do estudo fitoquímico de P. prunifolia com a análise dos extratos etanólicos obtidos a partir de suas raízes e galhos levou ao isolamento de cinco alcaloides indol-b-carbolínicos dos quais, dois derivados, o 10-hidróxi-iso-deppeaninol e o N-óxido-10-hidróxi-antirhina são descritos pela primeira vez. As estruturas foram determinadas por análise de técnicas espectroscópicas de IV, EMAR e RMN ( 1 H e 13 C, 1D e 2D). A avaliação da atividade frente à Leishmania amazonensis e Trypanosoma cruzi, mostrou que os extratos brutos e os alcaloides 14-oxoprunifoleína e estrictosamida inibiram as formas promastigotas de L. amazonensis, com valores de CI 50 de 16,0 e 40,7 mg per mL, respectivamente.

J natural products, 2021

The seeds of the akuamma tree (Picralima nitida) have been used as a traditional treatment for pain and fever. Previous studies have attributed these effects to a series of indole alkaloids found within the seed extracts; however, these pharmacological studies were significantly limited in scope. Herein, an isolation protocol employing pH-zone-refining countercurrent chromatography was developed to provide six of the akuamma alkaloids in high purity and quantities sufficient for more extensive biological evaluation. Five of these alkaloids, akuammine (1), pseudo-akuammigine (3), akuammicine (4), akuammiline (5), and picraline (6), were evaluated against a panel of >40 central nervous system receptors to identify that their primary targets are the opioid receptors. Detailed in vitro investigations revealed 4 to be a potent kappa opioid receptor agonist, and three alkaloids (1−3) were shown to have micromolar activity at the mu opioid receptor. The mu opioid receptor agonists were further evaluated for analgesic properties but demonstrated limited efficacy in assays of thermal nociception. These findings contradict previous reports of the antinociceptive properties of the P. nitida alkaloids and the traditional use of akuamma seeds as analgesics. Nevertheless, their opioid-preferring activity does suggest the akuamma alkaloids provide distinct scaffolds from which novel opioids with unique pharmacologic properties and therapeutic utility can be developed.

CHEMICAL & PHARMACEUTICAL BULLETIN, 2006

The genus Turraeanthus (Meliaceae) occurs in tropical and subtropical regions and comprises about four species in Cameroon. 1) These species have been used in Cameroonian traditional medicine for the treatment of cardiovascular disease, stomach ache, rheumatism pains, and asthma. 2) Phytochemical studies on the seeds of Turraeanthus africanus (WELW. ex. C.D.C.) PELLEGR. revealed the presence of labdane diterpenoids and a limonoid. In this paper, we describe the isolation and structural elucidation of two new alkaloids from T. africanus. The dried and ground stem bark of T. africanus was extracted with methanol. This extract was concentrated to dryness under a vacuum. Extensive column chromatography of the residue on silica gel yielded pure 10-O-demethyl-17-O-methyl isoarnottianamide (1) and 11-demethoxyl-12methoxyl oxynitidine (2), together with two known compounds that were characterized based on their spectral data, and identified as decarine, and oxynitidine. 6) Alkaloid 1, obtained as brown crystals, mp 237-239 °C, reacted positively to FeCl 3 reagent suggesting the presence of a phenolic hydroxyl group. Its high resolution electrospray-TOF mass spectrum (HR-ES-IMS) showed a pseudomolecu-lar ion peak (MϩH) ϩ at m/z 382.1283 (Calcd for C 21 H 20 O 6 N, 382.1285). The odd mass at m/z 381 indicated that it contained a nitrogen atom in the molecule. Its IR spectrum showed absorption bands for free hydroxyl at 3450 cm Ϫ1 , olefin (1631, 1517 cm Ϫ1 ), carbonyl (1663 cm Ϫ1 ), and ether (1285, 1142 cm Ϫ1 ) functionalities. The UV spectrum of compound 1 exhibited absorption maxima at 237, 291, and 332 nm. The 1 H-NMR signals at d 2.90 (3H) and d 8.25 (1H) were typical of an N(CH 3 )CHO group in compound 1. 7) This was confirmed in the 13 C-NMR spectrum by signals at d 32.6 and 163.3. Alkaloid 1 has also characteristic signals due to four aromatic protons appearing as, singlets at d 7.01, 7.40, 6.60, and 6.51, and a pair of doublet at d 7.80 (1H, Jϭ8.7 Hz) and 7.25 (1H, Jϭ8.7 Hz). On the other hand, the singlets of the aromatic rings should be located in para positions, and the two doublets indicated that the two aromatic protons were

Molecules, 2017

The genus Psychotria (Rubiaceae) comprises more than 2000 species, mainly found in tropical and subtropical forests. Several studies have been conducted concerning their chemical compositions, showing that this genus is a potential source of alkaloids. At least 70 indole alkaloids have been identified from this genus so far. This review aimed to compile 13 C-NMR data of alkaloids isolated from the genus Psychotria as well as describe the main spectral features of different skeletons.

Journal of Natural Products, 1990

AssTrucr.-Phytochemical studies on the aerial parts and bulbs of Narcisswpanizzianw collected in Milaga, Spain, resulted in the isolation of five Amaryllidaceae alkaloids. Three of them were identified as homolycorine, pretazettine, and galanthine 131. T h e fourth and 6fch compounds were determined as papyramine [I] and 6-epi-papyramine [2] which have now been completely characterized by means of two-dimensional nmr experiments.

2010