Total synthesis and biological activities of (+)- and (-)-boscialin and their 1'-epimers

An Updated Review on Nelumbo Nucifera Gaertn: Chemical Composition, Nutritional Value and Pharmacological Activities

Nelumbo nucifera Gaertn is a recognised herbal plant in ancient medical sciences. Each portion of the plant leaf, flower, seed and rhizome is utilised for nutritional and medicinal purposes. The chemical compositions like phenol, alkaloids, glycoside, terpenoids and steroids have been isolated. The plant contains various nutritional values like lipids, proteins, amino acids, minerals, carbohydrates, and fatty acids. Traditional medicine confirms that the phytochemicals of plants give significant benefits to the treatment of various diseases such as leukoderma, smallpox, dysentery, haematemesis, coughing, haemorrhage, metrorrhagia, haematuria, fever, hyperlipidaemia, cholera, hepatopathy and hyperdipsia. To verify the traditional claims, researchers have conducted scientific biological in vivo and in vitro screenings, which have exhibited that the plant keeps various notable pharmacological activities such as anticancer, hepatoprotective, antioxidant, antiviral, hypolipidemic, anti-obesity, antipyretic, hypoglycaemic, antifungal, anti-inflammatory and antibacterial activities. This review, summaries the nutritional composition, chemical constituents and biological activities substantiated by the researchers done in vivo and in vitro.

Towards the development of analytical monograph specifications for the quality assessment of the medicinal plant Phyllanthus urinaria

Many people in developing countries rely on herbal remedies for their primary healthcare needs. The challenge however is that several of these products lack proper documentation of quality and safety. To ensure consistent quality, validated methods are needed to establish and control quality attributes associated with identity, purity, and levels of bioactive constituents of the respective herbal materials. The present study focused on Phyllanthus urinaria (PU), a widely used medicinal plant in Ghana and West Africa that lacks the necessary quality control standards. The study aimed to develop an HPTLC identification method, which together with UPLC-ESI-Q-TOF-MS/MS analysis established the identity of PU samples and differentiated PU from other closely related Phyllanthus species. Quantitative UPLC and HPTLC methods were developed to assess the contents of selected active markers in the PU samples, which invariably led to the proposal of acceptance criteria for the active markers. Prior to the content analyses, the sample extraction procedure was optimized through the use of Design of Experiment method. The effects of harvest time and geographic origin on the content of active compounds were demonstrated in the investigations. PU samples were also found to be contaminated with higher levels of pesticides like chlorpyrifos and folpet. Essentially, this study provides analytical protocols, insights into the quality status of PU samples in Ghana, and analytical specifications contained in a drafted monograph for future consideration in regional and subregional African pharmacopoeias.

Spiro[3.5]nonenyl Meroterpenoid Lactones, Cryptolaevilactones G-L, an Ionone Derivative, and Total Synthesis of Cryptolaevilactone M from Cryptocarya laevigata

A CH3OH-CH2Cl2 (1:1) extract (N025439) of the leaves and twigs of Cryptocarya laevigata furnished eight new compounds, 1-8. Based on extensive 1D and 2D NMR spectroscopic data examination, the new δ-lactone derivatives 1-6 are monoterpene-polyketide hybrids containing a unique spiro[3.5]nonenyl moiety. Their trivial names, cryptolaevilactones G-L, follow those of the related known meroterpenoids cryptolaevilactones A-F. Cryptolaevilactone L (6) contains 11,12-cis-oriented substituents, while the other cryptolaevilactones contain trans-oriented groups. The structure of the linear δ-lactone 7, cryptolaevilactone M, was characterized from various spectroscopic data analysis, and the absolute configuration was determined by total synthesis through stereoselective allylation and Grubbs olefin metathesis. Compound 8 was elucidated to be an ionone derivative with a 3,4-syn-diol functionality.

Chemical Constituents of the Leaves of Peltophorum pterocarpum and Their Bioactivity

Two new sesquiterpenoids peltopterins A and B (compounds 1 and 2) and fifty-two known compounds were isolated from the methanol extract of P. pterocarpum and their chemical structures were established through spectroscopic and mass spectrometric analyses. The isolates 40, 43, 44, 47, 48, 51 and 52 exhibited potential inhibitory effects of superoxide anion generation or elastase release.

Anti-inflammatory flavonol acylglycosides from the aerial part of Lindera akoensis Hayata

Flavonol acylglycosides, linderakosides A–E (1–5) were characterized from L. akoensis. Compounds 1, 2, and 5 exhibited showed in vitro anti-inflammatory activity decrease the LPS-stimulated production of nitrite in RAW 264.7 cell.

Isoprenoid glycosides from Liriosma ovata

A methanol extract of the dried bark of Liriosma ovata afforded two new isoprenoid glycosides, a eudesmane sesquiterpene, 1alpha(beta- d-glucopyranosyloxy)eudesma-3alpha,4beta, 11-triol ( 1), and a C 13-norisoprenoid, 3alpha,6alpha-dihydroxymegastigman-7-en-9-one 3- O-beta- d-apiofuranosyl-(1-->6)-beta- d-glucopyranoside ( 2), as well as a known constituent, isopropyl-beta- d-apiofuranosyl-(1-->6)-beta- d-glucopyranoside ( 3). The structures of 1 and 2 were determined using spectroscopic methods. The methanol extract had a significant topical anti-inflammatory activity (ID 50, dose inducing 50% edema inhibition = 780 microg/cm (2)) about 8 times less than that of indomethacin (ID 50, 93 microg/cm (2)) assayed by the croton oil ear test in mice. In addition, the chloroform extract and compounds 1 and 2 showed weak antimicrobial activity against S taphylococcus aureus (MIC = 5.1, 2.1, and 4.0 mg/mL, respectively) using a broth microdilution assay.

Anticandidal low molecular compounds from higher plants with special reference to compounds from essential oils

The most active low molecular weight compounds from higher plants against Candida species are compiled from a database of antimicrobials (Amicbase) to find out new hints on their mechanism of action. The selected compounds possess strong inhibitory activities in vitro against Candida species either in the agar diffusion test, bioautography, agar dilution test, serial dilution test, or activity in the vapour phase. The test conditions are listed thoroughly and aspects of the different methods and recent developments in the testing of anticandidal drugs are discussed. The anticandidal spectra of drugs, antiseptics, and disinfectants licensed on the major markets are given for comparison of activities with compounds from natural sources. So far known mechanisms of action are described and some new structure-activity relationships are deduced from relationships between biological activities and chemical and physical parameters. Main specific targets of natural anticandidals are the ergosterol pathway, respiratory chain, and chitin biosynthesis.

Phytotoxic and antimicrobial activities of catechin derivatives

(+/-)-Catechin is a potent phytotoxin, with the phytotoxicity due entirely to the (-)-catechin enantiomer. (+)-Catechin, but not the (-)-enantiomer, has antibacterial and antifungal activities. Tetramethoxy, pentaacetoxy, and cyclic derivatives of (+/-)-catechin retained phytotoxicity. The results indicate that antioxidant properties of catechins are not a determining factor for phytotoxicity. A similar conclusion was reached for the antimicrobial properties. Centaurea maculosa (spotted knapweed) exudes (+/-)-catechin from its roots, but the flavanol is not re-absorbed and hence the weed is not affected. The much less polar tetramethoxy derivative may, however, be absorbed and hence be able to cause toxicity. Because of the combination of phytotoxicity and antimicrobial activity, (+/-)-catechin could be a useful natural herbicide and antimicrobial.

Alkaloids and limonoids from Bouchardatia neurococca: systematic significance

Five alkaloids, four beta-indoloquinazoline and one furoquinoline, and four terpenoids, three limonoids and one modified sesquiterpene, have been obtained from the aerial parts of Bouchardatia neurococca (Rutaceae). Two of the alkaloids, 1,2-dihydroxyrutaecarpine and 2-(2-[3-formylindolyl])-(3H)-quinazolin-4-one (bouchardatine), and two of the limonoids, 23-oxo-21xi-hydroxy-21,23-dihydroveprisone (veprisonic acid) and 21-oxo-23xi-hydroxy-21,23-dihydroveprisone (isoveprisonic acid) are new. The pattern of secondary metabolites isolated is rather unusual in the Rutaceae and is reminiscent of Tetradium, a genus with which Bouchardatia has not previously been associated.