Determination of bioactive markers in Cleome droserifolia using cell-based bioassays for antidiabetic activity and isolation of two novel active compounds

The antidiabetic activities of the aqueous (AqEx) and ethanolic (AlEx) extracts of Cleome droserifolia (Forssk.) Del., were tested in cultured C2C12 skeletal muscle cells and 3T3-L1 adipocytes. An 18-h treatment with the AqEx increased basal glucose uptake by 33% [insulin equivalent (IE)=1.3±0.04] in muscle cells comparable to a 25.5% increase caused by 100 nM insulin (IE=1±0.03). Fractionation of the tested AqEx yielded hexane (HxFr), chloroform (ClFr) and ethyl acetate (EtFr) fractions which exerted 38, 52 and 35% increase in the glucose uptake corresponding to an IE of 1.5±0.06, 2.0±0.04 and 1.4±0.04, respectively. Only the ClFr and EtFr accelerated the triglyceride accumulation [rosiglitazone equivalent (RE) was 0.9±0.13 and 0.63±0.12, respectively] in pre-adipocytes undergoing differentiation comparably with 10 μM rosiglitazone. Six terpenoids (C1-C6) and three flavonol glycosides (F1-F3) were isolated from the active ClFr and EtFr, respectively, and identified. C5, C2 and C4 had an IE of 0.86±0.05, 1.01±0.04 and 0.9±0.08, while F1, F2 and F3 gave an IE of 1.3±0.05, 2.3±0.05 and 2.0±0.04, respectively. We could conclude that the reported antihyperglycemic activity of Cleome droserifolia is attributed to significant insulin-like effects in peripheral tissues, and that compounds F2 and F3, being highly active, could be used as bioactive markers to standardize the C. droserifolia herbal extract.     

Prolyl endopeptidase inhibitors from Syzygium samarangense (Blume) Merr. & L. M. Perry

Compounds isolated from the hexane extract of the leaves of Syzygium samarangense (Blume) Merr. & L. M. Perry were tested for inhibitory activity against the following serine proteases: trypsin, thrombin and prolyl endopeptidase. The compounds were identified as an intractable mixture of alpha-carotene and beta-carotene (1), lupeol (2), betulin (3), epi-betulinic acid (4), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (5), 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (6), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (7), 2',4'-dihydroxy-6'-methoxy-3'-methyldihydrochalcone (8) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (9). Hydrogenation of compounds 5, 6 and 7 yielded compound 8, 2'-hydroxy-4',6'-dimethoxy-3'-methyldihydrochalcone (10) and 2',4'-dihydroxy-6'-methoxy-3',5'-dimethyldihydrochalcone (11), respectively. The hydrogenated products of compounds 6 and 7 were also tested for enzyme inhibitory activity. In addition, beta-sitosterol (12) and beta-D-sitosterylglucoside (13) were also isolated. This is the first report of the isolation of compounds 1-6, 8 and 13 from this plant. Compounds 3-8 and 10 exhibited significant and selective inhibition against prolyl endopeptidase among three serine proteases. This is the first report of this kind of activity for all these compounds.     

Six new dihydrobenzofuran lignans from the branches and leaves of Illicium wardii and their cytotoxic activities

Six new dihydrobenzofuran lignans, named illiciumlignans A⿿F (compounds 1⿿6), along with 15 known compounds (7⿿21) were isolated from the branches and leaves of Illicium wardii. The structures of 1⿿6 were determined using a combination of 1D and 2D NMR, HR-ESI⿿-MS, and CD spectroscopic data. Illiciumlignan D (4) is the first reported dihydrobenzofuran lignan arabinofuranoside that is derivatized with the arabinofuranose moiety on C-9⿲. Compounds 1⿿21 were evaluated for cytotoxic activity against four human cancer cell lines. Compounds 8, 12 and 20 exhibited significant activity against human cancer cell lines (A549, SKOV3, HepG2 and HCT116), with IC₅₀ values ranging from 2.7 to 14.9 μM.     

Cochlioquinone Derivatives with Apoptosis‐Inducing Effects on HCT116 Colon Cancer Cells from the Phytopathogenic Fungus Bipolaris luttrellii L439

A new cochlioquinone derivative, cochlioquinone F ( 1 ), as well as three known compounds, anhydrocochlioquinone A ( 2 ), isocochlioquinone A ( 3 ), and isocochlioquinone C ( 4 ), were isolated from the PDB (potato dextrose broth) culture of the phytopathogenic fungus Bipolaris luttrellii. The structure of 1 was elucidated on the basis of NMR techniques. The apoptosis‐inducing effects of compounds 1 – 4 were evaluated against HCT116 cancer cells. Compound 2 exhibited the strongest activity in inducing apoptosis on HCT116 cells within the range of 10–30 μM . In addition, the caspase activation, the release of cytochrome c from mitochondria, and the downregulation of Bcl‐2 protein in HCT116 cells treated with compound 2 were detected.     

Cytotoxic 7,20-epoxy ent-kauranoids from Isodon xerophilus

Four 7,20-epoxy ent-kaurane diterpenoids, xerophilusins G (1) and I-K (2-4), were isolated from the leaves of Isodon xerophilus, along with four known ones, enanderianin C (5), rosthorin A (6), longikaurin B (7), and rabdoternin D (8). Their structures were determined primarily using NMR spectroscopic techniques. The structure and stereochemistry of 3 were confirmed by X-ray crystallography. Compounds 4 and 7 exhibited broad cytotoxicity against four kinds of human tumor cells (K562, HL-60, HCT, and MKN-28 cells) in the range of 2.23-15.35 and 0.30-8.61 microg/ml, respectively.     

Cytotoxic oligophenols from the rhizome of Wikstroemia indica

A new tricoumarin glycoside, triumbelletin-7-O-β-d-glucoside (1) and a new biflavonoid, wikstroflavone A (2), together with two known compounds, wikstaiwanone A (3) and wikstaiwanone B (4), were isolated from the rhizome of Wikstroemia indica. The structures of new compounds were elucidated by extensive spectroscopic techniques (UV, IR, HRESIMS, 1D, 2D NMR and CD), in combination with quantum chemical calculations of ¹³C NMR and ECD spectra. All isolates were tested for their antineoplastic activities against cancer-derived cell lines HCT116, SW480, U87 and T98G. Compounds 2–4 exhibited moderate cytotoxic activities to the four cell lines. The flow cytometry assay and western blot analysis revealed that the cytotoxic effects were possibly attributed to the induced apoptotic cell death.     

Two New Sesquiterpene Derivatives from the Tunisian Endemic Ferula tunetana Pom.

A new sesquiterpene ester, tunetanin A ( 1 ), a new sesquiterpene coumarin, tunetacoumarin A ( 2 ), together with eight known compounds, i.e., coladin ( 3 ), coladonin ( 4 ), isosmarcandin ( 5 ), 13‐hydroxyfeselol ( 6 ), umbelliprenin ( 7 ) propiophenone ( 8 ), β‐sitosterol ( 9 ), and stigmasterol ( 10 ), were isolated from the roots of Ferula tunetana. Their structures were elucidated on the basis of extensive spectroscopic methods, including 1D‐ and 2D‐NMR experiments and MS analysis, as well as by comparison with published data. The cytotoxicity of compounds 1 – 7 towards two human colon cancer cell lines, HT‐29 and HCT 116, was evaluated. Compounds 3, 4 , and 6 showed weak cytotoxic activities.     

Chemical constituents and biological activities of Senecio aegyptius var. discoideus Boiss

A new eremophilane sesquiterpene, 1-beta-hydroxy-8-oxoeremophila-7,9-dien-12-oic acid (1), in addition to two known flavonol glycosides, rutin (2) and quercetin-3-O-glucoside-7-O-rutinoside (3), was isolated from the ethyl acetate fraction obtained from the aqueous alcoholic extract of the aerial parts of Senecio aegyptius var. discoideus Boiss. (family Asteraceae). The chemical structures of the isolated compounds were established by 1D and 2D NMR analysis (1H, 13C, COSY, HMQC, HMBC), MS and UV data, and through comparison with the literature. The ethyl acetate fraction and the isolated rutin showed significant cytotoxic activity against colorectal carcinoma (HCT 116) and to less extent against brain (U 251) and breast carcinoma (MCF 7). The ethyl acetate fraction showed a significant level of activity against Klebsiella pneumoniae, while the total extract showed the best antifungal activity against Candida albicans and Saccharomyces cerevisiae. DPPH radical scavenging activity of the ethyl acetate fraction was significant (96.7%) when compared to ascorbic acid. It also showed anti-inflammatory activity but no diuretic effect.     

Nortriterpenoids from the roots of Paeonia emodi

Chemical investigation of chloroform–ethyl acetate extract from the roots of Paeonia emodi yielded four hitherto unknown noroleanane triterpenoids (1–4) together with four known compounds (5–8). Their structures were established by analysis of spectroscopic data. Compounds 1–8 were evaluated for cytotoxic activities against human cancer cell lines A549, HL-60, HCT116 and ZR-75-30. Compounds 1, 2, 3, 6 and 7 showed modest cytotoxicity against HL-60, HCT116 and ZR-75-30.     

Anticancer potential of 3-(arylideneamino)-2-phenylquinazoline-4(3H)-one derivatives

Different quinazoline derivatives have showed wide spectrum of pharmacological activities. Some 3-(arylideneamino)-phenylquinazoline-4(3H)-ones have been reported to possess antimicrobial activity. The present study has been undertaken to evaluate the anticancer effect of these quinazolinone derivatives. The quinazolinone derivatives were synthesized as reported earlier. Compounds containing NO(2), OH, OCH(3), or OH and OCH(3) as substituent(s) on the arylideneamino group were named as P(3a), P(3b), P(3c), and P(3d) respectively. Out of these, P(3a) and P(3d) showed better cytotoxic activity than P(3b) and P(3c) on a panel of six cancer cell lines of different origin, namely, B16F10, MiaPaCa-2, HCT116, HeLa, MCF7, and HepG2, though the effect was higher in B16F10, HCT116, and MCF7 cells. P(3a) and P(3d) induced death of B16F10 and HCT116 cells was associated with characteristic apoptotic changes like cell shrinkage, nuclear condensation, DNA fragmentation, and annexin V binding. Also, cell cycle arrest at G1 phase, alteration of caspase-3, caspase-9, Bcl-2 and PARP levels, loss of mitochondrial membrane potential, and enhanced level of cytosolic cytochrome c were observed in treated B16F10 cells. Treatment with multiple doses of P(3a) significantly increased the survival rate of B16F10 tumor bearing BALB/c mice by suppressing the volume of tumor while decreasing microvascular density and mitotic index of the tumor cells.     

Two new resorcinol derivatives with strong cytotoxicity from the roots of Ardisia brevicaulis Diels

Two new resorcinol derivatives, 4-hydroxy-2-methoxy-6-[(8Z)-pentadec-8-en-1-yl]phenyl acetate (1) and 4-hydroxy-2-methoxy-6-pentadecylphenyl acetate (2), together with known compounds ardisiphenol D (3), 5-tridecylresorcinol (4), 5-pentadecylresorcinol (5), 5-[(8Z)-pentadec-8-en-1-yl]resorcinol (6), belamcandaquinones C and D (7 and 8, resp.), ardisicrenoside A, ardisiacrispin B, (22E)-24-ethyl-5α-cholesta-7,22-dien-3-one, and (22E)-24-ethyl-5α-cholesta-7,22-dien-3β-ol were isolated from the MeOH extract of the roots of Ardisia brevicaulis Diels. Their structures were determined by spectroscopic analysis including ESI- and EI-MS, and NMR data. Cytotoxicities of 1-4 against cell lines A549, MCF-7, and PANC-1 were tested in vitro by the MTT (=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. Compounds 1-4 showed cytotoxic activity against all cell lines stronger than that of cisplatin against A549.     

Trinorcucurbitane and cucurbitane triterpenoids from the roots of Momordica charantia

Five cucurbitacins, kuguacins A-E (1-5), together with three known analogues, 3beta,7beta,25-trihydroxycucurbita-5,(23E)-diene-19-al (6), 3beta,25-dihydroxy-5beta,19-epoxycucurbita-6,(23E)-diene (7), and momordicine I (8), were isolated from roots of Momordica charantia. Structures of 1-5 were elucidated by NMR and MS spectroscopic analysis. Among them, compounds 3-5 possess an unprecedented 25,26,27-trinorcucurbitane backbone. Compounds 3 and 5 showed moderate anti-HIV-1 activity with EC(50) values of 8.45 and 25.62 microg/ml, and exerted minimal cytotoxicity against C8166 cells (IC(50)>200 microg/ml), with a selectivity index more than 23.68 and 7.81, respectively.     

Alkaloids from Cephalotaxus lanceolata and Their Cytotoxicities

A phytochemical investigation of the branches and leaves of Cephalotaxus lanceolata resulted in the isolation of three new cephalotaxus alkaloids, cephalancetines A, B, and D ( 1, 2 , and 4 , resp.), together with ten known alkaloids, 3 and 5 – 13 . The structures of the alkaloids were elucidated on the basis of spectroscopic analyses, including 1D‐ and 2D‐NMR, and HR‐ESI‐MS, and single‐crystal X‐ray diffraction. All isolated compounds were tested for their cytotoxicities against four human tumor cell lines, A549, HCT116, SK‐BR‐3, and HepG2. Compounds 12 and 13 showed remarkable activities against A549, HCT116, and HepG2 cell lines.     

Two novel phenylacetoxylated p-terphenyls from Thelephora ganbajun Zang

Two novel phenylacetoxylated p-terphenyl derivatives, namely ganbajunin F (6'-methoxy-2'-phenylacetoxy-3', 4, 4", 5'-tetrahydroxy- p-terphenyl), and ganbajunin G (5'-methoxy-2'-phenylacetoxy-3', 4, 4", 6'-tetrahydroxy-p-terphenyl), together with a known compound cycloleucomelone were isolated from the fruiting bodies of Thelephora ganbajun Zang. Their structures were established on the basis of spectral (MS, IR, NMR, HMBC, HMQC measurement) and chemical evidence.     

Characteristic Steroids from the South China Sea Gorgonian Muricella sibogae and Their Cytotoxicities

Twenty‐four steroid‐based natural products, 9,10‐secosteroids ( 1 – 10 ), 1,4‐dien‐3‐one steroids ( 11 – 19 ), and 4‐en‐3‐one steroids ( 20 – 24 ), containing varying side‐chains, were isolated from the South China Sea gorgonian Muricella sibogae. The structures of one new 9,10‐secosteroid, sibogol D ( 1 ), and two new 1,4‐dien‐3‐one steroids, sibogols E and F ( 11 and 12 ), were elucidated by extensive spectroscopic analyses and by comparison with the literature data. Cytotoxicities for all the isolates were evaluated against four selected tumor cell lines, HL‐60, HCT116, K562, and P388. Compounds 3, 9 , and 13 exhibited potent cytotoxic activities against the HL‐60 cell line, with IC₅₀ values ranging from 1.27 to 10.05 μM , and compound 3 was also cytotoxic against HCT116 with an IC₅₀ value of 5.8 μM . The bioassay results also indicated a potential relationship between structural patterns and activity. The newly presented series of 1,4‐dien‐3‐one and 4‐en‐3‐one types of steroids relating to the unique 9,10‐secosteroids in biogenesis were found in this species for the first time, which is of considerable chemotaxonomic significance.     

Induction of autophagy by dimethyl cardamonin is associated with proliferative arrest in human colorectal carcinoma HCT116 and LOVO cells

Dimethyl cardamonin (2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone; DMC) is a naturally occurring chalcone, and it is the major compound isolated from the leaves of Syzygium samarangense (Blume) Merr. & L.M. Perry (Myrtaceae). Experiments were conducted to determine the effects of DMC on cell proliferation, cell-cycle distribution, and programmed cell death in cultures of human colorectal carcinoma HCT116 and LOVO cells. Results showed that DMC inhibited HCT116 and LOVO cell proliferation and induced G(2) /M cell cycle arrest, which was associated with the conversion of microtubule associated protein light chain 3 (LC3)-I-LC3-II, an autophagosome marker, and the incorporation of monodansylcadaverine (MDC), a marker for the acidic compartment of autolysosomes or acidic vesicular organelles. The treatment of HCT116 and LOVO cells using a combination of DMC with an autophagy inhibitor, such as 3-methyladenine (3-MA), beclin 1 siRNA, or atg5 siRNA, suppressed the effect of DMC-mediated anti-proliferation. These results imply that DMC can suppress colorectal carcinoma HCT116 and LOVO cell proliferation through a G(2) /M phase cell-cycle delay, and can induce autophagy, the hallmark of Type II programmed cell death (PCD). Taken together, our results suggest that DMC may be an effective chemotherapeutic agent for HCT116 and LOVO colorectal carcinoma cells.     

Bioprospection of Cytotoxic Compounds in Fungal Strains Recovered from Sediments of the Brazilian Coast

The cytotoxic activities of extracts (50 μg/ml) from 48 fungal strains, recovered from sediments of Pecém's offshore port terminal (Northeast coast of Brazil), against HCT‐116 colon cancer cell lines were investigated. The most promising extract was obtained from strain BRF082, identified as Dichotomomyces cejpii by phylogenetic analyses of partial RPB2 gene sequence. Thus, it was selected for bioassay‐guided isolation of the cytotoxic compounds. Large‐scale fermentation of BRF082 in potato dextrose broth, followed by chromatographic purification of the bioactive fractions from the liquid medium, yielded gliotoxin ( 4 ) and its derivatives acetylgliotoxin G ( 3 ), bis(dethio)bis(methylsulfanyl)gliotoxin ( 1 ), acetylgliotoxin ( 5 ), 6‐acetylbis(dethio)bis(methylsulfanyl)gliotoxin ( 2 ), besides the quinazolinone alkaloid fiscalin B. All isolated compounds were tested for their cytotoxicities against the tumor cell lines HCT‐116, revealing 4 and 3 as the most cytotoxic ones (IC₅₀ 0.41 and 1.06 μg/ml, resp.).     

Homoisoflavanones from Disporopsis aspera

From cytotoxic extracts of the roots of Disporopsis aspera Engl. (Liliaceae) a homoisoflavanone, disporopsin (3-(2',4'-dihydroxy-benzyl)-5,7-dihydroxy-chroman-4-one) (1) and three rare methyl-homoisoflavanones, 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-chroman-4-one (2), 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6,8-dimethyl-chroman-4-one (3) and 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-8-methoxy-chroman-4- one (4) along with five other known compounds, N-trans-feruloyl tyramine (5), adenine (6), 5-(hydroxymethyl)-2-furfural (7), beta-sitosterol (8) and beta-sitosteryl glucopyranoside (9) were isolated. The structures of compounds 1-2 were elucidated by spectral data (1, 2-D NMR and EIMS). The four homoisoflavanones (1-4) were found to be cytotoxic against a series of human cancer cell lines (HCT15, T24S, MCF7, Bowes, A549 and K562) with IC(50) ranging from 15 to 200 microM. Possible biosynthesis routes for homoisoflavonoids (1-4) are discussed.     

Cytotoxic abietane diterpenes from Hyptis martiusii Benth

From roots of Hyptis martiusii Benth. two tanshinone diterpenes were isolated, the new 7beta-hydroxy-11,14-dioxoabieta-8,12-diene (1) in addition to the known 7alpha-acetoxy-12-hydroxy-11,14-dioxoabieta-8,12-diene (7alpha-acetoxyroyleanone) (2). Structures of 1 and 2 were established by spectroscopic means. The cytotoxic activity against five cancer cell lines was evaluated. Compounds 1 and 2 displayed considerable cytotoxic activity against several cancer cell lines with IC50 values in the range of 3.1 to 11.5 microg/ml and 0.9 to 7.6 microg/ml, respectively. The cytotoxic activity seemed to be related to inhibition of DNA synthesis, as revealed by the reduction of 5-bromo-2'-deoxyuridine incorporation and induction of apoptosis, as indicated by the acridine orange/ethidium bromide assay and morphological changes after 24 h of incubation in leukemic cells.     

Chaephilones A and B,Two New Azaphilone Derivatives Isolated from Chaetomium globosum

Two new azaphilone derivatives, chaephilones A ( 1 ) and B ( 2 ), were isolated from the fungus Chaetomium globosum, together with four structurally related analogs 3  –  6 . The structures of 1 and 2 were elucidated by comprehensive spectroscopic analyses including HR‐ESI‐MS and NMR. The known compounds were identified as chaetomugilin Q ( 3 ), chaetomugilin D ( 4 ), 11‐epichaetomugilin A ( 5 ), and chaetomugilin S ( 6 ) by comparing their NMR data and optical rotation values with those reported. Compound 2 represents the first example of azaphilone with an open furan ring. Compounds 1 and 2 were evaluated for cytotoxic activities against five human cancer cell lines (HL‐60, SMMC‐7721, A‐549, MCF‐7, and SW480) by the MTS method.