A new benzoquinone and a new stilbenoid from Paphiopedilum exul (Ridl.) Rolfe.

One new alkyl benzoquinone, paphionone (1), one new trans-stilbenoid, (E)-6,5'-dihydroxy-2,3'-dimethoxystilbene (2), and eight known stilbenoids and flavonoids (3-10) were isolated from the leaves and roots of Paphiopedilum exul (Orchidaceae). Their chemical structures were determined based on IR, ECD, MS and NMR analyses. Cytotoxicity of all isolated compounds towards human hepatocellular carcinoma (HepG2) cell line was examined in vitro by MTT assay. The para-hydroxybenzyl substituted stilbene 10 was potently cytotoxic to the cancer cells, with an IC50 value of 4.80 ± 1.10 µM (selectivity index = 20.83). All compounds were non-toxic to normal human embryo fibroblast (OUMS-36) cell line.

Correction: Nukulkit et al. Eight Indole Alkaloids from the Roots of Maerua siamensis and Their Nitric Oxide Inhibitory Effects. Molecules 2022, 27, 7558.

After a proofreading check, some experimental data were inconsistent with the supplementary information in the original publication [...].

Antinociceptive efficacy of Clerodendrum petasites S. Moore, a Thai medicinal plant, and its CNS safety profiles.

Background: Clerodendrum petasites, an herbal plant in Thailand, has been used for many years in folk medicine. However, scientific evidence regarding CNS safety pharmacology and antinociceptive activity of C. petasites (CP) has not yet been well characterized. Purpose: The present study aimed to assess the CNS safety pharmacology and antinociceptive and antiinflammatory effects of CP extract. Methods: The effect of CP extract on CNS safety pharmacology was assessed using LABORAS automated home cage monitoring and rotarod test. Its pharmacological activity was evaluated both in-vitro, and in-vivo using hot-plate, acetic acid-induced writhing, formalin, and carrageenan-induced paw edema models. Results and conclusion: CP extract significantly improved thermal and chemical nociceptive behaviors and acute inflammatory pain at all doses: 300, 600, and 1200 mg/kg, p.o. The antiinflammatory effect of CP extract in inflammatory pain models was comparable to the effect of positive control: indomethacin 10 mg/kg at all dose levels tested. Further, the CP extract at 600 mg/kg dose significantly inhibited 82.3% of carrageenan-induced total edema. In-vitro, CP extract at 12.5, 25, and 50 µg/mL concentrations significantly reduced the expression of LPS-induced nitric oxide, IL-6, and TNF-α expression in both RAW 264.7 macrophage and BV-2 microglial cell lines. In addition, CP extract did not show any potential effects on the CNS, indicated by no significant effects on motor coordination, spontaneous locomotor activity, general behaviors, and well-being compared to vehicle-treated mice (p > 0.05). Overall, the present study evidences the potential antinociceptive, antiinflammatory efficacies of CP extract with a favorable CNS safety profile.

Three new cytotoxic stilbene dimers from paphiopedilum dianthum.

Three new stilbene dimers, paphiodianthins A-C (1-3), and nine known stilbenes, lignan and flavonoids (4-12) were isolated from the roots and leaves of Paphiopedilum dianthum (Orchidaceae). The structures of new compounds were elucidated from their NMR, HRESIMS and IR spectroscopic data. Cytotoxic activity of all isolated compounds was evaluated by in vitro MTT assay against two human cancer cell lines (MCF-7, Caco-2), doxorubicin-resistant and mitoxantrone-resistant MCF-7 sublines, as well as a normal cell line (NIH/3T3). Stilbenes 1, 3, 10 and 11 were strongly cytotoxic to both cancer cell lines with IC50 values ranging from 0.50 to 4.51 µM. Compounds 1, 10 and 11 were also active against chemotherapy-resistant MCF-7 sublines.

Anticancer and chemosensitizing activities of stilbenoids from three orchid species.

Recently, we have isolated and identified several bioactive flavonoids and stilbenoids with potential anticancer activity from Thai orchids. In this study, we further investigated the cytotoxic and chemosensitizing activities of these phytochemicals (namely, pinocembrin, cardamonin, isalpinin, galangin, pinosylvin monomethyl ether, 2,3'-dihydroxy-5'-methoxystilbene, (E)-2,5'-dihydroxy-2'-(4-hydroxybenzyl)-3'-methoxystilbene, 2,3-dihydroxy-3',5'-dimethoxystilbene, 2,3'-dihydroxy-5,5'-dimethoxystilbene, 3,4'-dihydroxy-5-methoxystilbene and batatasin III) against breast cancer MCF7 cells and its two multidrug resistant (MDR) sublines (MCF7/DOX and MCF7/MX). Cytotoxicity was determined with MTT assay for the estimation of the half maximal cytotoxic concentrations (IC50). Effects of the test compounds on activities of efflux transporters (BCRP, P-gp, MRP1, and MRP2) were evaluated with substrate accumulation assays using fluorometry and flow cytometry analysis. Out of these 11 test compounds, the stilbene pinosylvin monomethyl ether displayed its cytotoxicity specifically toward MCF7 cells (IC50 = 6.2 ± 1.2 µM, 72-h incubation) with 4.96 folds higher than normal fibroblast. Its potency decreased in MCF7/DOX and MCF7/MX cells by 3.94 and 7.38 folds, respectively. Our transporter assay indicated that this stilbene significantly reduced the activities of P-gp, MRP1, and MRP2, but not BCRP. After 48-h co-incubation, this stilbene (at 2 µM) synergistically increased doxorubicin- and mitoxantrone-mediated cytotoxicity in MCF7, MCF7/DOX, and MCF7/MX cells potentially by increasing the intracellular level of cytotoxic drug. Pinosylvin monomethyl ether could sensitize breast cancer cells to chemotherapy and overcome MDR, in part, via the inhibition of drug efflux transporters.

Eight Indole Alkaloids from the Roots of Maerua siamensis and Their Nitric Oxide Inhibitory Effects.

Maerua siamensis (Capparaceae) roots are used for treating pain and inflammation in traditional Thai medicine. Eight new indole alkaloids, named maeruanitriles A and B, maeroximes A-C, and maeruabisindoles A-C, were isolated from them. Spectroscopic methods and computational analysis were applied to determine the structure of the isolated compounds. Maeroximes A-C possesses an unusual O-methyloxime moiety. The bisindole alkaloid maeruabisindoles A and B possess a rare azete ring, whereas maeruabisindole C is the first indolo[3,2-b]carbazole derivative found in this plant family. Five compounds [maeruanitriles A and B, maeroxime C, maeruabisindoles B, and C] displayed anti-inflammatory activity by inhibiting nitric oxide (NO) production in the lipopolysaccharide-induced RAW 264.7 cells. Maeruabisindole B was the most active inhibitor of NO production, with an IC50 of 31.1 ± 1.8 µM compared to indomethacin (IC50 = 150.0 ± 16.0 µM) as the positive control.

N-Trans-p-Coumaroyltyramine Enhances Indomethacin- and Diclofenac-induced Apoptosis Through Endoplasmic Reticulum Stress-dependent Mechanism in MCF-7 Cells.

BACKGROUND/AIM: The anticancer potential of indomethacin and diclofenac has been reported against several types of cancer cells. In this study, we investigated the enhancement effect of a coumaric acid derivative found in some Piper plants, N-trans-p-coumaroyltyramine (TCT) on indomethacin and diclofenac cytotoxicity in breast cancer cells. MATERIALS AND METHODS: MCF-7 and mitoxantrone-resistant MCF-7 (MCF-7/MX) cancer cells were treated with indomethacin or diclofenac in the presence of TCT for 48 h. Cell viability, apoptosis, mitochondrial function and signaling proteins were assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Hoechst 33342, tetramethyl-rhodamine-ethyl-ester and western blot analysis, respectively. RESULTS: Combination treatment resulted in significant reduction of cell viability and mitochondrial membrane potential, whereas the ratio of BCL2-associated X, apoptosis regulator to BCL2 apoptosis regulator, and apoptosis increased. The enhancing effect of TCT was related to reduced nuclear factor-erythroid factor 2-related factor 2/heme oxygenase-1 expression, and increased activation of the protein kinase RNA-like endoplasmic reticulum kinase/eukaryotic initiation factor 2 alpha/activating transcription factor 4/C/EBP homologous protein signaling pathways. CONCLUSION: TCT in combination with indomethacin or diclofenac promoted endoplasmic reticulum stress-dependent apoptosis in breast cancer cells.

A new dihydrophenanthrene from Cymbidium finlaysonianum and structure revision of cymbinodin-A.

1-(4-Hydroxybenzyl)-4,6-dimethoxy-9,10-dihydrophenanthrene-2,7-diol (13), a new dihydrophenanthrene, was isolated along with ferulic acid esters (1), eight phenanthrene derivatives (2, 3, 6-11) and three bibenzyls (4, 5, 12) from an epiphytic orchid, Cymbidium finlaysonianum. The molecular structure of cymbinodin-A (2) was revised based on spectroscopic data and comparison with the literature. Compounds 2, 3, and 6-13 were evaluated and shown to be cytotoxic against human small cell lung cancer (NCI-H187) cell line. Cymbinodin-A displayed the highest cytotoxicity with an IC50 value of 3.73 µM.

Flavonoids kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone inhibit mitotic clonal expansion and induce apoptosis during the early phase of adipogenesis in 3T3-L1 cells.

OBJECTIVE: Kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone (DTMC) are two major flavonoids found in Chromolaena odorata Linn. leaf extract. The aim of this study was to elucidate the mechanism by which these two flavonoids exerted their effect on adipogenesis. The inhibitory effect of kaempferide and DTMC on adipocyte differentiation and their mechanisms involving mitotic clonal expansion (MCE) and apoptosis during the early stage of adipogenesis were investigated. METHODS: Confluent 3T3-L1 preadipocytes were induced to differentiate and exposed to the flavonoids during various phases of differentiation. Intracellular lipid accumulation, cell density and expression of the transcription factors peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding proteins α were assessed using AdipoRed, Oil red O and Western blot assays. Effects of both flavonoids on cell proliferation and apoptosis were also determined by carboxyfluorescein diacetate succinimidyl ester and annexin V-fluorescein isothiocyanate/propidium iodide-staining assays, respectively. RESULTS: Kaempferide and DTMC showed significant, concentration-dependent anti-adipogenic activity and effect on cell density in the early phase of adipogenesis. The expression of the transcription factors seemed to be reduced when the treatment was prolonged or in the early phase of adipogenesis. These flavonoids interrupted MCE via inhibition of preadipocyte proliferation and induction of apoptosis. DTMC was nearly three times more potent than kaempferide in inducing apoptosis. CONCLUSION: Kaempferide and DTMC exerted their anti-adipogenic activity through inhibition of MCE, either by suppressing cell proliferation or by inducing apoptosis during the early phase of differentiation.

Anti-adipogenic effect of flavonoids from Chromolaena odorata leaves in 3T3-L1 adipocytes.

OBJECTIVE: The leaves of Chromolaena odorata, a highly invasive shrub found growing wild worldwide, are traditionally used for wound healing. Due to its high flavonoid contents, we aimed to find a new application for this plant. Preliminary tests using its ethanolic leaf extract showed that it could suppress the accumulation of lipids in adipocytes. We therefore studied the anti-adipogenic effect of several C. odorata leaf extracts and the relationship between molecular structure and bio-activity of its isolated flavonoid constituents using 3T3-L1 preadipocytes/adipocytes as a model. METHODS: Three leaf extracts and thirteen flavonoids isolated from C. odorata were tested for their effect on lipid accumulation in 3T3-L1 adipocytes using AdipoRed reagent, with quercetin as the positive control. The effects of active flavonoids on the adipocytes were confirmed by oil red O staining and visualized under a light microscope. RESULTS: n-Hexane and ethyl acetate extracts of C. odorata leaves displayed anti-adipogenic activity. The latter extract was the more potent one, especially at 40 µg/mL. Four flavonoids, pectolinarigenin, kaempferide, 4,2'-dihydroxy-4',5',6'-trimethoxychalcone and dillenetin, exhibited significant, concentration-dependent inhibitory effects on lipid accumulation in 3T3-L1 adipocytes. The most potent flavonoid obtained in this study was 4,2'-dihydroxy-4',5',6'-trimethoxychalcone, which caused 75% and 90% inhibition of cellular lipid accumulation at 30 and 50 µmol/L, respectively. Both kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone were major constituents in the ethyl acetate extract of this plant. CONCLUSION: C. odorata leaves contained several flavonoids with anti-adipogenic effects against lipid accumulation in 3T3-L1 adipocytes. The plant, normally considered a useless weed, may actually provide an abundant source of biologically active flavonoids.

Cytotoxic activity of the chemical constituents of Clerodendrum indicum and Clerodendrum villosum roots.

OBJECTIVE: The roots of two Thai medicinal plants, Clerodendrum indicum and Clerodendrum villosum are found in traditional medicine practices. The aim of this research was to preliminarily study the cytotoxicity of extracts of their roots, and the parts that possessed cytotoxic activity were separated on a chromatograph to identify their active compounds. METHODS: The extracts of both plants were screened for cytotoxicity on the SW620 cell line and the compounds isolated from the active extracts were further evaluated for their cytotoxic activity against five human cancer cell lines, including SW620, ChaGo-K-1, HepG2, KATO-III and BT-474 using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. RESULTS: Dichloromethane extracts of C. indicum and C. villosum were active against the SW620 cell line. Triterpenoids were mostly obtained from the extracts of these plants (0.28% and 1.02%, respectively) and exhibited varying degrees of cytotoxicity and specificity against the tested cell lines. Two triterpenoids, oleanolic acid 3-acetate and betulinic acid, displayed moderate to strong cytotoxicity toward all cancer cell lines, with 50% inhibitory concentration (IC50) values of 1.66-20.49 µmol/L, whereas 3ß-hydroxy-D:B-friedo-olean-5-ene and taraxerol were cytotoxic to only the SW620 cell line (IC50 = 23.39 and 2.09 µmol/L, respectively). Triterpenoid, lupeol, showed potent cytotoxicity on both SW620 (IC50 = 1.99 µmol/L) and KATO-III cell lines (IC50 = 1.95 µmol/L), while a flavonoid, pectolinarigenin, displayed moderate cytotoxicity against these cells (IC50 = 13.05 and 24.31 µmol/L, respectively). Although the widely distributed steroid, stigmasterol, was effective against the SW620 cell line (IC50 = 2.79 µmol/L) and ß-sitosterol was also active against SW620 (IC50 = 11.26 µmol/L), BT-474 (IC50 = 14.11 µmol/L) and HepG2 cancer cells (IC50 = 20.47 µmol/L), none of the characteristic 24ß-ethylsteroids of either Clerodendrum species were shown to be cytotoxic. CONCLUSION: This study is the first report on the presence of cytotoxic triterpenoids from the roots of these medicinal plants, which have been used in herbal formulas as an antipyretic. Our findings support further in-depth study of this pharmacological activity as an anticancer agent.

Benzophenones and xanthone derivatives from Garcinia schomburgkiana-induced P-glycoprotein overexpression in human colorectal Caco-2 cells via oxidative stress-mediated mechanisms.

BACKGROUND: Up-regulation of P-gp is an adaptive survival mechanism of cancer cells from chemotherapy. Three new phytochemicals including two benzophenones, guttiferone K (GK) and oblongifolin C (OC), and a xanthone, isojacaruebin (ISO), are potential anti-cancer agents. However, the capability of these compounds to increase multidrug-resistance (MDR) through P-gp up-regulation in cancer cells has not been reported. PURPOSE: This study was to investigate the effects of GK, OC and ISO on P-gp up-regulation in colorectal adenocarcinoma cells (Caco-2 cells). In addition, the mechanisms underlying their inductive effect were also determined. METHODS: The inductive effect of GK, OC and ISO on P-gp expression at transcription level was measured by real-time reverse transcription polymerase chain reaction. The reactive oxygen species production was determined by 2', 7'-dichlorofluorescin diacetate assay. The protein content of P-gp and involvement of mitogen-activated protein kinases (MAPK) pathway was evaluated by western blot analysis. RESULTS: GK, OC and ISO (50 µM, 24 h) were able to increase the amount of MDR1 mRNA and protein in Caco-2 cells. The presence of N-acetyl-l-cysteine significantly prevented the inductive effect of GK, OC and ISO on MDR1 mRNA level. Moreover, MAPK inhibitors including U0126 (an ERK1/2/MAPK inhibitor) and SB202190 (p38/MAPK inhibitor) suppressed an increase of MDR1 mRNA levels in the cells treated with benzophenones (GK, OC) and xanthone ISO, respectively. These findings were in agreement with the increase of phosphorylated form of either ERK1/2 (p-ERK1/2) or p38 (p-p38) upon treatment of the cells with these three compounds. In addition, OC and ISO, but not GK, increased mRNA of c-Jun level. CONCLUSION: The benzophenones GK, OC and xanthone ISO are likely MDR inducers through up-regulation of P-gp expression at transcription level. Their molecular mechanisms involve oxidative stress-mediated activation of MAPK signaling pathway.

Cytotoxic stilbenes from the roots of Paphiopedilum godefroyae.

Two new stilbenes, 2-(3',5'-dimethoxyphenyl)-6-hydroxy-5-methoxybenzofuran (1) and 3'-hydroxy-2,5'-dimethoxystilbene (2), together with seven known stilbenes (3, 5-10) and one flavanone (4), were isolated from the roots of Paphiopedilum godefroyae. Their chemical structures were determined on the basis of their spectroscopic data. These isolated compounds were evaluated for their cytotoxicity against human small cell lung cancer (NCI-H187) cell lines and an arylbenzofuran derivative, 5,6-dimethoxy-2-(3-hydroxy-5-methoxyphenyl)benzofuran (6), was shown to be strongly cytotoxic with an IC50 value of 5.10 µM.

A new biphenyl and other constituents from the wood of Garcinia schomburgkiana.

A new biphenyl, named schomburgbiphenyl (1), and 14 known compounds were isolated from the wood of Garcinia schomburgkiana. The known constituents were identified as follows: three xanthones (2, 8 and 9), two benzophenones (3 and 4), three biphenyls (5-7), three biflavonoids (10-12) and three steroids. Compounds 3 and 4 were highly cytotoxic to SW620 cell line (100 times more than the positive control, doxorubicin) and were also strongly active against KATO-III, HepG2 and CHAGO cell lines. Compound 6 was specifically cytotoxic towards SW620 cells, whereas compound 8 displayed strong cytotoxicity against all five cell lines tested.

New sesquiterpenes and phenolic compound from Ficus foveolata.

Two new eudesmane-type sesquiterpenes, named foveolide A (1) and foveoeudesmenone (2), one new sesquiterpenoid dimer, foveolide B (3) and a new phenolic compound, foveospirolide (4), were isolated along with six known compounds, including 4(15)-eudesmene-1ß, 6α-diol (5), 4(15)-eudesmene-1ß, 5α-diol (6), friedelin, taraxerol, betulin and ethyl rosmarinate, from the stems of Ficus foveolata. The structures of these new compounds were characterized by spectroscopic methods (IR, MS and NMR). Compound 1 exhibited moderate cytotoxicity against SW620, HepG2, BT474 and KATO-III cancer cell lines, whereas compound 3 was specifically cytotoxic toward SW620 cell line.

Biologically active constituents of Aglaia erythrosperma.

From the fruits and leaves of Aglaia erythrosperma (Meliaceae), 10 chemical constituents were isolated and identified, i.e. the dammarane triterpenoids cabraleadiol (1), cabraleahydroxylactone (2), ethyl eichlerianoate (3), eichlerialactone (4), aglinin A (5), cabralealactone (6), the aglaialactone 5,6-desmethylenedioxy-5-methoxy-aglalactone (7), the flavagline 4'-demethoxy-3',4'-methylenedioxy-methyl rocaglate (8) and two coumarins: scoparone and scopoletin. Flavagline 8 exhibited antimalarial activity with an IC(50) value of 7.30 µg mL(-1) and was strongly cytotoxic against small cell lung cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines, with IC(50) values of 2.17, 2.10 and 0.11 µg mL(-1), respectively. Aglinin A (5) displayed moderate cytotoxicity against all the three cancer cell lines, whereas ethyl eichlerianoate (3), cabralealactone (6) and the aglaialactone 7 were exclusively cytotoxic to NCI-H187 cell line. Cabraleahydroxylactone (2) showed antiviral activity against herpes simplex virus type-1 with an IC(50) value of 3.20 µg mL(-1), in comparison with the standard acyclovir (IC(50) = 1.90 µg mL(-1)). When tested for antimycobacterial activity against Mycobacterium tuberculosis H(37)Ra, compounds 1-4 and 6-8 displayed minimum inhibitory concentration in the range of 25-50 µg mL(-1).

A new 1,3-diketofriedelane triterpene from Salacia verrucosa.

A new 1,3-diketofriedelane triterpene, 21α-hydroxyfriedelane-1,3-dione (1) together with six known friedelane triterpenes, 30-hydroxyfriedelane-1,3-dione (2), friedelane-1,3-dione (3), 26-hydroxyfriedelane-1,3-dione (4), friedelin (5), 21α-hydroxy-D:A-friedo-olean-3-one (6) and kokoonol (7), were isolated from the stems of Salacia verrucosa (Celastraceae). The structures of these triterpenes were characterized by spectroscopic methods (IR, MS and NMR). Compound 3 was strongly cytotoxic against SW620 cell line, whereas compounds 4 and 6 were moderately active against SW620, HepG2 and KATO-III cancer cell lines.

A new acyclic diterpene acid and bioactive compounds from Knema glauca.

Investigation of the chemical constituents of the fruits of Knema glauca (Myristicaceae) yielded a new acyclic diterpene acid, named glaucaic acid 4, together with four acylphenols, including 1-(2,6-dihydroxyphenyl) tetradecan-1-one 1, malabaricone A 6, dodecanoylphloroglucinol 7 and 1-(2,4,6-trihydroxyphenyl)-9-phenylnonan-1-one 8, two lignans sesamin 2 and asarinin 3, and a flavan, myristinin D 5. In addition, myristinin A 9 and (+/-)-7,4'-dihydroxy-3'-methoxyflavan 10 were isolated from its leaves and stems, respectively. When tested against small-cell lung cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines, compounds 1, 6-8 and 10 displayed weak to moderate cytotoxicity. The acylphenols 6-8 displayed antituberculosis activity against the microbe Mycobacterium tuberculosis with MIC values of 25, 50 and 100 microg/mL, respectively, and antiviral activity against herpes simplex virus type 1, with 7 as the most active compound (IC(50) = 3.05 microg/mL). Malabaricone A 6 was also active against the malarial parasite Plasmodium falciparum with an IC(50) value of 2.78 microg/mL.

A new arylnaphthalene lignan from Knema furfuracea.

A new arylnaphthalene lignan, named furfuracin, was isolated from the leaves of Knema furfuracea (Myristicaceae), whereas 7 known compounds including (+)-trans-1,2-dihydrodehydroguaiaretic acid, fragransin A(2), biochanin A, gingkolic acid, anarcardic acid, 2-hydroxy-6-(12-phenyldodecyl)-benzoic acid and 2-hydroxy-6-(12-phenyldodecen-8'Z-yl)-benzoic acid were obtained from its stems. The structure of the new lignan was established by analysis of spectroscopic data (UV, IR, MS and NMR).

Canarosine: a new guanidine alkaloid from Canavalia rosea with inhibitory activity on dopamine D1 receptors.

A new acyclic guanidine alkaloid, canarosine (1), together with five known compounds, beta-sitosterol (2), stigmasterol (3), daucosterol (4), epi-inositol 6-O-methyl ether (5), and rutin (6), were isolated from the aerial parts of Canavalia rosea. Their structures were established on the basis of their spectroscopic data. In the radioligand receptor binding assay, canarosine (1), at a concentration of 100 microg/ml, caused 91% inhibition of the dopamine D1 receptor binding with an IC50 value of 39.4 +/- 5.8 microM.