A new coumarin, 8,4''-dihydroxy-3'',4''-dihydrocapnolactone-2',3'-diol (1) and two known triterpenes, 5(6)-gluten-3-one (2) and 5(6)-gluten-3alpha-ol (3) were isolated from the leaves of Micromelum minutum (Rutaceae) collected from Sepilok, Sabah, Malaysia and their structures were characterized by spectroscopic methods.
A new cycloartane, monocarpinine (1), incorporating a fused tetrahydrofuranyl ring, and a cytotoxic tetracyclic lactam, monomarginine (2), were isolated from a stem bark extract of the Malayan species Monocarpia marginalis. The structures of these compounds were determined using NMR and MS analysis. Monomarginine (2) showed appreciable cytotoxicity toward human KB (both drug-sensitive and drug-resistant) and Jurkat cells.
Plant resins, and particularly dammars from the Dipterocarpaceae family, were widely used in the past, notably as part of caulking material. The organic composition of resins, already complicated, is not always preserved over time and can be considerably affected by ageing. Hence, their occurrence in archaeological items leads to the necessity to identify them taxonomically with precision. Resinous organic materials collected near and/or on wrecks discovered in South China Sea, supposed to contain dammar resins because of their geographical excavation context, were investigated by gas chromatography-mass spectrometry (GC-MS), together with freshly collected dammars, to establish taxonomic and alteration parameters allowing to identify dammar even in very altered samples or in mixtures together with other organic materials. This study specially focuses on three samples collected within or close to the M1J wreck, a Portuguese wreck lost in the Straight of Malacca during the 16th century. Our analyses establish that all three are made of dammar, two of them in association with pitch and bitumen. In addition, biodegradation biomarkers were detected in all these three samples, indicating that they were submitted to microbial degradation processes during their ageing.
Bioassay-guided fractionation of a MeOH extract of tubers of Coleus tuberosus afforded the active anti-tumor-promoting compounds identified as the triterpenoid 2alpha,3beta-dihydroxyolean-12-en-28-oic acid (maslinic acid; CT2) and a phytosterol mixture (CT1). CT1 consists of stigmasterol (32%), beta-sitosterol (40.3%), and campesterol (27.7%) as determined by capillary gas chromatography. CT1 and CT2 showed very strong anti-tumor-promoting activities at IC(50) 0.7 microg/ml and 0.1 microg/ml, respectively, in a convenient, short-term in vitro assay, i.e., the inhibition of Epstein-Barr virus (EBV) activation induced by phorbol 12-myristate 13-acetate (PMA) and sodium butyrate. We report for the first time the anti-tumor-promoting activity of 2alpha,3beta-dihydroxyolean-12-en-28-oic acid and show that a mixture of stigmasterol, beta-sitosterol, and campesterol is more potent than the individual components in inhibiting tumor-promoting activity.
Successive extraction of the dried leaves of Melastoma malabathricum, followed by purification using repeated chromatographic techniques, yielded six compounds, including two amides, auranamide and patriscabratine, a triterpene, alpha-amyrin, and three flavonoids, quercitrin, quercetin and kaempferol-3-O-(2'',6''-di-O-p-trans-coumaroyl)-beta-glucoside. Their structures were elucidated by spectroscopic means and also by direct comparison of their spectroscopic data with respective published data. These three phenolic constituents were found to be active as free radical scavengers, with quercetin being the strongest radical scavenger, having an IC(50) value of 0.69 microM in the UV method. Quercitrin and kaempferol-3-O-(2'',6''-di-O-p-trans-coumaroyl)-beta-glucoside showed moderate radical scavenging, with IC(50) values of 74.1 and 108.8 microM, respectively.
An easy and efficient strategy to prepare betulinic acid esters with various anhydrides was used by the enzymatic synthesis method. It involves lipase-catalyzed acylation of betulinic acid with anhydrides as acylating agents in organic solvent. Lipase from Candida antarctica immobilized on an acrylic resin (Novozym 435) was employed as a biocatalyst. Several 3-O-acyl-betulinic acid derivatives were successfully obtained by this procedure. The anticancer activity of betulinic acid and its 3-O-acylated derivatives were then evaluated in vitro against human lung carcinoma (A549) and human ovarian (CAOV3) cancer cell lines. 3-O-glutaryl-betulinic acid, 3-O-acetyl-betulinic acid, and 3-O-succinyl-betulinic acid showed IC(50)<10 microg/ml against A549 cancer cell line tested and showed better cytotoxicity than betulinic acid. In an ovarian cancer cell line, all betulinic acid derivatives prepared showed weaker cytotoxicity than betulinic acid.
Chronic inflammation is one of the predisposing factors for neoplastic transformation. Targeting inflammation through suppression of the pro-inflammatory pathway by dietary phytochemicals provides an important strategy for cancer prevention. Maslinic acid is a novel natural triterpenoid known to inhibit proliferation and induce apoptosis in some tumor cell lines. Although maslinic acid has cytotoxic and pro-apoptotic effects on cancer cells, the underlying mechanisms of its effects on the inflammatory pathway have yet to be elucidated. It has been reported that abnormal expression of pro-inflammatory enzyme cyclooxygenase-2 (COX-2) causes promotion of cellular proliferation, suppression of apoptosis, enhancement of angiogenesis and invasiveness. In the present study, the suppressive effect of maslinic acid on COX-2 expression and the binding activity of upstream transcription factors NF- κB and AP-1, which are known to regulate COX-2 transcriptional activation, were assessed using Raji cells. The anti-inflammatory action of maslinic acid was benchmarked against oleanolic acid and other standard drugs. Western blot analysis and electrophoretic mobility shift assay (EMSA) were employed to analyze COX-2 expression as well as NF- κB and AP-1 binding activity. Our results showed that maslinic acid suppresses COX-2 expression in a concentration-dependent manner. Likewise, the constitutive nuclear NF- κB (p65) activity as well as phorbol 12-myristate 13-acetate (PMA)- and sodium N-butyrate (SnB)-induced AP-1 binding activity in Raji cells were significantly reduced following treatment with maslinic acid. Since maslinic acid suppresses COX-2 expression in Raji cells at concentrations that also lowered the NF- κB (p65) and AP-1 binding activity, it is possible that the suppression of COX-2 by this natural triterpenoid might be achieved, at least in part, via the NF- κB and AP-1 signaling pathways.
Andrographis paniculata (AP), Centella asiatica (CA) and Orthosiphon stamineus (OS) are three popular herbs traditionally used worldwide. AP is known for the treatment of infections and diabetes and CA is good for wound healing and healthy skin while OS is usually consumed as tea to treat kidney and urinary disorders. Interaction of these herbs with human cytochrome P450 2C19 (CYP2C19), a major hepatic CYP isoform involved in metabolism of many clinical drugs has not been investigated to date.
A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4ɛ-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.
There has been considerable effort to discover plant-derived antibacterials against methicillin-resistant strains of Staphylococcus aureus (MRSA) which have developed resistance to most existing antibiotics, including the last line of defence, vancomycin. Pentacyclic triterpenoid, a biologically diverse plant-derived natural product, has been reported to show anti-staphylococcal activities. The objective of this study is to evaluate the interaction between three pentacyclic triterpenoid and standard antibiotics (methicillin and vancomycin) against reference strains of Staphylococcus aureus.
Leaves of Centella asiatica (Centella) were analysed for their triterpene composition and bioactivity such as collagen enhancement, antioxidant, anticellulite and UV protection capacity properties. Triterpenes of Centella were measured using HPLC-PAD on an Excil ODS 5 mm (C18) column for the simultaneous determination of asiatic acid, madecassic acid, asiaticoside and madecassoside. Centella was found to contain significant amounts of madecassoside (3.10 ± 4.58 mg/mL) and asiaticoside (1.97 ± 2.65 mg/mL), but was low in asiatic and madecassic acid. The highest collagen synthesis was found at 50 mg/mL of Centella extracts. The antioxidant activity of Centella (84%) was compared to grape seed extract (83%) and Vitamin C (88%). Its lipolytic activity was observed by the release of glycerol (115.9 µmol/L) at 0.02% concentration. Centella extracts exhibited similar UV protection effect to OMC at 10% concentration. In view of these results, the potential application of Centella in food and pharmaceutical industries is now widely open.
The asiatic acid, a triterpenoids isolated from Centella asiatica was used to delineate its inhibitory effect on acetylcholinesterase (AChE) properties, excitatory post synaptic potential (EPSP) and locomotor activity. This study is consistent with asiatic acid having an effect on AChE, a selective GABA(B) receptor agonist and no sedative effect on locomotor.
Lantadenes are pentacyclic triterpenoids present in the leaves of the plant Lantana camara. In the present study, in vitro antioxidant activity and free radical scavenging capacity of lantadene A was evaluated using established in vitro models such as ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH•), hydroxyl radical (OH•), nitric oxide radical (NO•), superoxide anion scavenging activities and ferrous ion chelating assay. Interestingly, lantadene A showed considerable in vitro antioxidant, free radical scavenging capacity activities in a dose dependant manner when compared with the standard antioxidant in nitric oxide scavenging, superoxide anion radical scavenging and ferrous ion chelating assay. These findings show that the lantadene A possesses antioxidant activity with different mechanism of actions towards the different free radicals tested. Since lantadene A is a very popular drug in modern medicine, it is a promising candidate for use as an antioxidant and hepatoprotective agent.
A study on the leaves of Aglaia exima led to the isolation of one new and seven known compounds: six triterpenoids and two steroids. Their structures were elucidated and analyzed mainly by using spectroscopic methods; 1D and 2D NMR, mass spectrometry, UV spectrometry and X-ray. All the triterpenoids and steroids were measured in vitro for their cytotoxic activities against eight cancer cell lines; lung (A549), prostate (DU-145), skin (SK-MEL-5), pancreatic (BxPC-3), liver (Hep G2), colon (HT-29), breast (MCF-7) and (MDA-MB-231). The new cycloartane triterpenoid, 24(E)-cycloart-24-ene-26-ol-3-one 1, showed potent cytotoxic activity against colon (HT-29) cancer cell line (IC(50) 11.5μM).
Five flavonoids, 5-hydroxy-(6:7,3':4')-di(2,2-dimethylpyrano)flavone 1, carpachromene 2, cycloartocarpesin 3, norartocarpetin 4 and 2'-hydroxy-4,4',6'-trimethoxychalcone 5, along with three triterpenes, friedelin 6, lupeol 7 and 13-sitosterol 8 were isolated for the first time from the leaves of Artocarpus fulvicortex F.M. Jarrett. The structures of these compounds were established by analysis of their spectroscopic (1D and 2D NMR) and spectrometric (MS) data, as well as by comparison of these with those reported in the literature.
The evolution of antibiotic resistance in Staphylococcus aureus showed that there is no long-lasting remedy against this pathogen. The limited number of antibacterial classes and the common occurrence of cross-resistance within and between classes reinforce the urgent need to discover new compounds targeting novel cellular functions not yet targeted by currently used drugs. One of the experimental approaches used to discover novel antibacterials and their in vitro targets is natural product screening. Three known pentacyclic triterpenoids were isolated for the first time from the bark of Callicarpa farinosa Roxb. (Verbenaceae) and identified as α-amyrin [3β-hydroxy-urs-12-en-3-ol], betulinic acid [3β-hydroxy-20(29)-lupaene-28-oic acid], and betulinaldehyde [3β-hydroxy-20(29)-lupen-28-al]. These compounds exhibited antimicrobial activities against reference and clinical strains of methicillin-resistant (MRSA) and methicillin-sensitive S. aureus (MSSA), with minimum inhibitory concentration (MIC) ranging from 2 to 512 μg/mL. From the genome-wide transcriptomic analysis to elucidate the antimicrobial effects of these compounds, multiple novel cellular targets in cell division, two-component system, ABC transporters, fatty acid biosynthesis, peptidoglycan biosynthesis, aminoacyl-tRNA synthetases, ribosomes and β-lactam resistance pathways are affected, resulting in destabilization of the bacterial cell membrane, halt in protein synthesis, and inhibition of cell growth that eventually lead to cell death. The novel targets in these essential pathways could be further explored in the development of therapeutic compounds for the treatment of S. aureus infections and help mitigate resistance development due to target alterations.
Garcinia hombroniana (seashore mangosteen) in Malaysia is used to treat itching and as a protective medicine after child birth. This study was aimed to investigate the bioactive chemical constituents of the bark of G. hombroniana. Ethyl acetate and dichloromethane extracts of G. hombroniana yielded two new (1, 9) and thirteen known compounds which were characterized by the spectral techniques of NMR, UV, IR and EI/ESI-MS, and identified as; 2,3',4,5'-tetrahydroxy-6-methoxybenzophenone(1), 2,3',4,4'-tetrahydroxy-6-methoxybenzophenone (2), 2,3',4,6-tetrahydroxybenzophenone (3), 1,3,6,7-tetrahydroxyxanthone (4), 3,3',4',5,7-pentahydroxyflavone (5),3,3',5,5',7-pentahydroxyflavanone (6), 3,3',4',5,5',7-hexahydroxyflavone (7), 4',5,7-trihydroxyflavanone-7-rutinoside (8), 18(13→17)-abeo-3β-acetoxy-9α,13β-lanost-24E-en-26-oic acid (9), garcihombronane B (10), garcihombronane D (11), friedelan-3-one (12), lupeol (13), stigmasterol (14) and stigmasterol glucoside (15). In the in vitro cytotoxicity against MCF-7, DBTRG, U2OS and PC-3 cell lines, compounds 1 and 9 displayed good cytotoxic effects against DBTRG cancer cell lines. Compounds 1-8 were also found to possess significant antioxidant activities. Owing to these properties, this study can be further extended to explore more significant bioactive components of this plant.
Recently, we have isolated koetjapic acid (KA) from Sandoricum koetjape and identified its selective anticancer potentiality against colorectal carcinoma. KA is quite likely to be useful as a systemic anticancer agent against colorectal malignancy. However, with extremely low solubility, KA has to be converted into a biocompatible solubilized form without compromising the bioefficacy. Objective of this study is to enhance solubility of KA and to evaluate anticancer efficacy of potassium koetjapate in human colorectal cancer cells.
A growing body of evidence suggests that activation of nuclear factor kappa B (NF-κB) signaling pathways is among the inflammatory mechanism involved in the development of insulin resistance and chronic low-grade inflammation in adipose tissues derived from obese animal and human subjects. Nevertheless, little is known about the roles of NF-κB pathways in regulating mitochondrial function of the adipose tissues. In the present study, we sought to investigate the direct effects of celastrol (potent NF-κB inhibitor) upon mitochondrial dysfunction-induced insulin resistance in 3T3-L1 adipocytes. Celastrol ameliorates mitochondrial dysfunction by altering mitochondrial fusion and fission in adipocytes. The levels of oxidative DNA damage, protein carbonylation and lipid peroxidation were down-regulated. Further, the morphology and quantification of intracellular lipid droplets revealed the decrease of intracellular lipid accumulation with reduced lipolysis. Moreover, massive production of the pro-inflammatory mediators tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were markedly depleted. Insulin-stimulated glucose uptake activity was restored with the enhancement of insulin signaling pathways. This study signified that the treatments modulated towards knockdown of NF-κB transcription factor may counteract these metabolic insults exacerbated in our model of synergy between mitochondrial dysfunction and inflammation. These results demonstrate for the first time that NF-κB inhibition modulates mitochondrial dysfunction induced insulin resistance in 3T3-L1 adipocytes.
Among the array of nanomaterials, carbon nanotubes have shown great potential as drug carriers in the field of nanomedicine, owing to their attractive physicochemical structure, which facilitates functionalization of therapeutic molecules onto their external walls or being encapsulated inside the tubes. The aim of this preliminary study was to formulate betulinic acid (BA), a poorly water-soluble drug, in oxidized multiwalled carbon nanotubes (MWCNT-COOH) for enhanced delivery efficiency into cancer cells with reduced cytotoxicity. The synthesized MWCNT-BA nanocomposite was characterized using ultraviolet-visible, Fourier transform infrared, thermogravimetric analysis, powder X-ray diffraction, and field emission scanning electron microscopy techniques. The loading of BA in MWCNT-COOH nanocarrier was estimated to be about 14.5%-14.8% (w/w), as determined by ultraviolet-visible and thermogravimetric analysis. Fourier transform infrared study shows that the peaks of the resulting MWCNT-BA nanocomposite correlate to the characteristic functional groups of BA and MWCNT-COOH. The powder X-ray diffraction results confirmed that the tubular structures of MWCNT-COOH were not affected by the drug loading mechanism of BA. The release profiles demonstrated that approximately 98% of BA could be released within 22 hours by phosphate-buffered saline solution at pH 7.4 compared with about 22% within 24 hours at pH 4.8. The biocompatibility studies revealed that MWCNT-BA at concentrations <50μg/mL expressed no cytotoxicity effects for mouse embryo fibroblast cells after 72 hours of treatment. The anticancer activity of MWCNT-BA was observed to be more sensitive to human lung cancer cell line when compared with human liver cancer cell line, with half maximal inhibitory concentration values of 2.7 and 11.0μg/mL, respectively. Our findings form a fundamental platform for further investigation of the MWCNT-BA formulation against different types of cancer cells.