Anti-inflammatory tirucallane triterpenoids from Anopyxis klaineana Pierre (Engl.), (Rhizophoraceae)

Chemical constituents of Entandrophragma angolense and their anti-inflammatory activity

From the stem bark of Entandrophragma angolense, six undescribed compounds were isolated, including seco-tirucallane type triterpenoids, limonoids, and a catechin glucoside, along with nineteen known structures. All structures were determined by interpretation of spectroscopic and HRMS data, and absolute configuration was confirmed with the aid of electronic circular dichroism. The isolated compounds were tested for LPS-induced NO inhibition in RAW 264.7 macrophages and EC₅₀ values for moluccensin O and (-)-catechin were 81 μM and 137 μM, respectively.

Systems Pharmacology Approach and Experiment Evaluation Reveal Multidimensional Treatment Strategy of LiangXueJieDu Formula for Psoriasis

Clinical studies have demonstrated the anti-psoriatic effect of the LiangXueJieDu (LXJD) herbal formula. However, the systemic mechanism and the targets of the LXJD formula have not yet been elucidated. In the present study, a systems pharmacology approach, metabolomics, and experimental evaluation were employed. First, by systematic absorption-distribution-metabolism-excretion (ADME) analysis, 144 active compounds with satisfactory pharmacokinetic properties were identified from 12 herbs of LXJD formula using the TCMSP database. These active compounds could be linked to 125 target proteins involved in the pathological processes underlying psoriasis. Then, the networks constituting the active compounds, targets, and diseases were constructed to decipher the pharmacological actions of this formula, indicating its curative effects in psoriasis treatment and related complications. The psoriasis-related pathway comprising several regulatory modules demonstrated the synergistic mechanisms of LXJD formula. Furthermore, the therapeutic effect of LXJD formula was validated in a psoriasis-like mouse model. Consistent with the systems pharmacology analysis, LXJD formula ameliorated IMQ-induced psoriasis-like lesions in mice, inhibited keratinocyte proliferation, improved keratinocyte differentiation, and suppressed the infiltration of CD3+ T cells. Compared to the model group, LXJD formula treatment remarkably reduced the expression of inflammatory cytokines and factors, such as IL-1β, IL-6, TNF-α, Cox2, and inhibited the phosphorylation of p-P65, p-IқB, p-ERK, p-P38, p-PI3K, p-AKT, indicating that LXJD formula exerts its therapeutic effect by inhibiting the MAPK, PI3K/AKT, and NF-қB signaling pathways. The metabolic changes in the serum of psoriasis patients were evaluated by liquid chromatography coupled with orbitrap mass spectrometry (LC-MS). The LXJD formula improved two perturbed metabolic pathways of glycerophospholipid metabolism and steroid hormone biosynthesis. Overall, this study revealed the complicated anti-psoriatic mechanism of LXJD formula and also offered a reliable strategy to elucidate the complex therapeutic mechanism of this Chinese herbal formula in psoriasis from a holistic perspective.

Bioactive constituents with antibacterial, resistance modulation, anti-biofilm formation and efflux pump inhibition properties from Aidia genipiflora stem bark

Background

Antimicrobial resistance is a global health challenge. The involvement of bacterial biofilms and efflux pumps in the development of multidrug resistance (MDR) is well established. Medicinal plants have been proposed as alternatives for combating MDR focusing on their bioactive constituents with resistance modulatory activities. This study was aimed at investigating the stem bark of Aidia genipiflora for bioactive constituents with anti-biofilm, efflux pump inhibition and resistance modulatory activities.

Method

The crude methanol extract was purified by column chromatography and isolated compounds characterized by mass and nuclear magnetic resonance spectrometry. Antibacterial activity was determined by the High-throughput spot culture growth inhibition and the broth micro-dilution assay. The ethidium bromide accumulation assay was used to determine efflux pump inhibition property. Biofilm inhibition was determined in a microplate crystal violet retention assay.

Results

Purification of the ethyl acetate fraction led to the isolation of oleanonic acid (1), 4-hydroxy cinnamic acid docosyl ester (2), β-stigmasterol/β-sitosterol (mixture 3a/b) and D-mannitol (4). The minimum inhibitory concentrations (MICs) ranged from 250 to > 500 μg/mL for extracts and fractions and from 15 to 250 μg/mL for compounds. In the presence of sub-inhibitory concentrations of the compounds, the MIC of amoxicillin against E. coli (20 μg/mL) and P. aeruginosa (320 μg/mL) was reduced by 32 and 10 folds respectively. The whole extract demonstrated anti-biofilm formation and efflux pump inhibition in E. coli, S. aureus and P. aeruginosa. The sterol mixture (3a/b) at concentration of 100 μg/mL caused the highest inhibition (73%) of biofilm formation in S. aureus. Oleanonic acid (1) demonstrated remarkable efflux pump inhibition at MIC of 7.8 μg/mL in E. coli better than the standard drugs verapamil and chlorpromazine.

Conclusion

This study confirms the prospects of A. genipiflora as a source of new antibacterial agents and adjuvants that could interact with some resistance mechanisms in bacteria to enhance the activity of hitherto ineffective antibiotics. “A small portion of the study has been presented in a conference in the form of poster”.

Antimicrobial pentacyclic triterpenes and glycosides from the stem bark of Cussonia bancoensis

The stem bark of Cussonia bancoensis is used traditionally for the treatment of different types of infection and pain. A bioassay guided fractionation of the methanol stem bark extract led to the isolation of five pentacyclic triterpenes and glycosides identified based on spectroscopic data as 23-hydroxyursolic acid (CB1), hederagenin (CB2), 3-O-α-L-arabinopyranosyl-echinocystic acid (CB3), 3-O-α-L-arabinopyranosyl- oleanolic acid (CB4) and 3-O-α-L-arabinopyranosyl-ursolic acid (CB5). CB2 - CB5 are being reported for the first time from this species. The compounds were evaluated for antimicrobial activity against ten microorganisms using the HT-SPOTi method. CB3 demonstrated remarkable antimicrobial activity against S. aureus, S. pyogens, E. faecalis, S. typhi and C. albicans at MICs between 3.12 and 12.5 µg/mL. Among the studied compounds, it was observed that hydroxylation of position C-16 of the oleanane skeleton may enhance antimicrobial activity. This study gives insight into the anti-infective constituents of the stem bark of C. bancoensis and justifies its use in ethnomedicine.[Formula: see text].

Triterpenoids

This review covers newly isolated triterpenoids that have been reported during 2015.

Plant triterpenoid saponins: biosynthesis, in vitro production, and pharmacological relevance

The saponins are a diverse class of natural products, with a broad scale distribution across different plant species. Chemically characterized as triterpenoid glycosides, they posses a 30C oxidosqualene precursor-based aglycone moiety (sapogenin), to which glycosyl residues are subsequently attached to yield the corresponding saponin. Based on the chemically distinct aglycone moieties, broadly, they are divided into triterpenoid saponins (dammaranes, ursanes, oleananes, lupanes, hopanes, etc.) and the sterol glycosides. This review aims to present in detail the biosynthesis patterns of the different aglycones from a common precursor and their glycosylation patterns to yield the functionally active glycoside. The review also presents recent advances in the pharmacological activities of these saponins, particularly as potent anti-neoplastic pharmacophores, antioxidants, or anti-viral/antibacterial agents. Since alternate production pedestals for these pharmacologically important triterpenes via cell and tissue cultures are an attractive option for their sustainable production, recent trends in the variety and scale of in vitro production of plant triterpenoids have also been discussed.

Kleinhospitine E and Cycloartane Triterpenoids from Kleinhovia hospita

A novel cycloartane triterpenoid alkaloid, kleinhospitine E (1), six new cycloartane triterpenoids (2-7), three known cycloartane triterpenoids (8-10), and taraxerone (11) were isolated from a methanol extract of Kleinhovia hospita. Their structures were elucidated by 1D- and 2D-NMR spectroscopy as well as HRMS analysis. The absolute configurations of all isolated compounds were determined from their ECD spectra by comparison with theoretical values. Kleinhospitine E (1) is the first cycloartane alkaloid possessing an unusual γ-lactam with an oxopropylidene side chain. Compounds 2, 3, and 6 were assigned as cycloartane triterpenoids with a 9α,10α-cyclopropyl ring, which is found rarely among naturally occurring compounds, while 4 and 5 were established as isomers of compound 3 containing a 21,23-diacetal side chain. Biological evaluation revealed that compounds 4 and 9 exhibited more potent antiproliferative activities against a multidrug-resistant tumor cell line compared with its parent chemosensitive cell line. Furthermore, compound 6 exhibited submicromolar anti-HIV activity.

Flavanones of Erythrina livingstoniana with antioxidant properties

Six new flavanones (1-6), together with six known compounds were isolated from Erythrina livingstoniana. Their structures were elucidated on the basis of NMR data and HRMS(n) fragmentation pathway and by comparison with literature data. Compounds 5, 7 and 8 showed remarkable DPPH free radical scavenging efficacies. The compounds, however, did not demonstrate an anti-inflammatory potential when tested using a PGE2 (prostaglandin E2) competitive enzyme immunoassay. The plausible biosynthetic pathways of the isolated compounds are described.