Chemical constituents and in vivo preliminary evaluation of the toxicological activity of Ouratea spectabilis (OCHNACEAE) and Clitoria guianensis (Fabaceae) leaves

Clitoria guianensis and Ouratea spectabilis, found in the Brazilian Cerrado, are used in folk medicine, despite the few chemical and biological studies reported in the literature. The present study aims to investigate the toxicity and effect of extracts from both species on the microcrustacean Artemia salina, and to determine the chemical composition of the hexane extract of O. spectabilis leaves and the EtOAc fraction of C. guianensis leaves. Kaempferitrin, a flavonoid isolated from of the EtOAc fraction of C. guianensis leaves, was identified by chemical analysis. Analysis of the hexane extract of O. spectabilis leaves using gas chromatography-mass spectrometry (GC-MS) suggested the presence of twenty-five known substances. The Hex, EtOAc, and EtOH crude extracts of C. guianensis leaves exhibited high and moderate toxicity against Artemia salina, with median lethal dose values (LD50) of 43.7, 25.4, and 233.4 mg.L−1, respectively. The acetone extract of O. spectabilis leaves showed moderate toxicity against Artemia salina with an LD50 value of 115.13 mg.L−1.

The Chemical Composition of Oils and Cakes of Ochna serrulata (Ochnaceae) and Other Underutilized Traditional Oil Trees from Western Zambia.

Currently, the negative effects of unified and intensive agriculture are of growing concern. To mitigate them, the possibilities of using local but nowadays underused crop for food production should be more thoroughly investigated and promoted. The soybean is the major crop cultivated for vegetable oil production in Zambia, while the oil production from local oil-bearing plants is neglected. The chemical composition of oils and cakes of a three traditional oil plant used by descendants of the Lozi people for cooking were investigated. Parinari curatellifolia and Schinziophyton rautanenii oils were chiefly composed of α-eleostearic (28.58-55.96%), linoleic (9.78-40.18%), and oleic acid (15.26-24.07%), whereas Ochna serrulata contained mainly palmitic (35.62-37.31%), oleic (37.31-46.80%), and linoleic acid (10.61-18.66%); the oil yield was high (39-71%). S. rautanenii and O. serrulata oils were rich in γ-tocopherol (3236.18 µg/g, 361.11 µg/g, respectively). The O. serrulata oil also had a very distinctive aroma predominantly composed of p-cymene (52.26%), m-xylene (9.63%), γ-terpinene (9.07%), o-xylene (7.97), and limonene (7.23%). The cakes remaining after oil extraction are a good source of essential minerals, being rich in N, P, S, K, Ca, and Mg. These plants have the potential to be introduced for use in the food, technical, or pharmaceutical industries.

Lophira alata Suppresses Phorbol Ester-Mediated Increase in Cell Growth via Inhibition of Protein Kinase C-α/Akt in Glioblastoma Cells.

BACKGROUND: Medicinal plants serve as sources of compounds used to treat other types of cancers. The root of the plant Lophira alata (Ochnaceae) has been used as a component of traditional herbal decoctions administered to cancer patients in southwestern Nigeria. However, the mechanism of the cytotoxic effects of Lophira alata alone or in the presence of phorbol ester has not been investigated in brain tumor cells. OBJECTIVE: This study aimed to examine the cytotoxic potential of the methanolic fraction of Lophira alata root on malignant glioma invasive cellular growth and survival. METHODS: The methanolic fraction of Lophira alata (LAM) was subjected to high-performance liquid chromatography to determine the fingerprints of the active molecules. The antiproliferative effects of Lophira alata were assessed using the MTT and LDH assays. Protein immunoblots were carried out to test the effects of Lophira alata, alone or in the presence of phorbol ester, on survival signaling pathways, such as Akt, mTOR, and apoptotic markers such as PARP and caspases. RESULTS: The methanolic fraction of Lophira alata (LAM) induced a concentration-dependent and time-dependent decrease in glioma cell proliferation. In addition, LAM attenuated phorbol ester-mediated signaling of downstream targets such as Akt/mTOR. Gene silencing using siRNA targeting PKC-alpha attenuated LAM-mediated downregulation of Akt. In addition, LAM induced both PARP and caspase cleavages. The HPLC fingerprint of the fraction indicates the presence of flavonoids. CONCLUSION: LAM decreases cell proliferation and induces apoptosis in glioma cell lines and thus could serve as a therapeutic molecule in the management of gliomas.

Antibacterial and cytotoxic biflavonoids from the root bark of Ochna kirkii.

The new isoflavonoid kirkinone A (1) and biflavonoid kirkinone B (2) along with six known compounds (3-8) were isolated from the methanolic extract of the root bark of Ochna kirkii. The compounds were identified by NMR spectroscopic and mass spectrometric analyses. Out of the eight isolated natural products, calodenin B (4) and lophirone A (6) showed significant antibacterial activity against the Gram-positive bacterium Bacillus subtilis with MIC values of 2.2 and 28 µM, and cytotoxicity against the MCF-7 human breast cancer cell line with EC50 values of 219.3 and 19.2 µM, respectively. The methanolic crude extract of the root bark exhibited cytotoxicity at EC50 8.4 µg/mL. The isolated secondary metabolites and the crude extract were generally inactive against the Gram-negative Escherichia coli (MIC ≥400 µg/mL). Isolation of biflavonoids and related secondary metabolites from O. kirkii demonstrates their chemotaxonomic significance to the genus Ochna and to other members of the family Ochnaceae.

Biflavanones, Chalconoids, and Flavonoid Analogues from the Stem Bark of Ochna holstii.

Two new biflavanones (1 and 2), three new bichalconoids (3-5), and 11 known flavonoid analogues (6-16) were isolated from the stem bark extract (CH3OH-CH2Cl2, 7:3, v/v) of Ochna holstii. The structures of the isolated metabolites were elucidated by NMR spectroscopic and mass spectrometric analyses. The crude extract and the isolated metabolites were evaluated for antibacterial activity against Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) as well as for cytotoxicity against the MCF-7 human breast cancer cell line. The crude extract and holstiinone A (1) exhibited moderate antibacterial activity against B. subtilis with MIC values of 9.1 µg/mL and 14 µM, respectively. The crude extract and lophirone F (14) showed cytotoxicity against MCF-7 with EC50 values of 11 µg/mL and 24 µM, respectively. The other isolated metabolites showed no significant antibacterial activities (MIC > 250 µM) and cytotoxicities (EC50 ≥ 350 µM).

The effect of the biflavonoid 2″,3″-dihydroochnaflavone on Trypanosoma cruzi Y strain.

Trypanosoma cruzi is the causative agent of Chagas disease which affects 8 million people in Latin America. The parasite possesses high capacity to evade host immune system and the available drugs to treat Chagas disease present low efficacy combined to serious side effects to patients. Therefore, the identification of alternative therapeutics is essential. Brazilian flora exhibits an immense diversity of metabolites with great potential to be developed into new drugs. We investigated the action of 2″,3″-dihydroochnaflavone a biflavonoid extracted from Luxemburgia nobilis Eichler ex Engl. (Ochnaceae) against T. cruzi (Y strain). Our experiments showed that this compound is effective against parasite epimastigote forms, presenting IC50 value of (2.5 ± 0.1) µM after 96 h of treatment. Ultrastructure alterations were also detected in treated epimastigotes especially mitochondrial enlargement at the kinetoplast region. At the concentration of 30 µM, the compound killed (61.6 ± 3.37)% of the parasite in its amastigote form. In addition, at the same concentration, the compound killed all trypamastigotes growing within murine macrophages after 7-9 days of infection. Nonetheless, the biflavonoid concentrations were harmless to murine enriched population of lymphocytes and peritoneal macrophages. These results indicate that 2″,3″- dihydroochnaflavone presents activity against T. cruzi.

(3,3″)-Linked Biflavanones from Ouratea spectabilis and Their Effects on the Release of Proinflammatory Cytokines in THP-1 Cells.

Ouratea spectabilis is an arborous species traditionally used in Brazil as an anti-inflammatory agent. Four new (3,3″)-linked biflavanone O-methyl ethers, named ouratein A (1), B (2), C (3), and D (4), were isolated from the bark extract of the species. Ouratein A (1) is an enantiomer of neochamagesmine A, which has never been described before. The structures were elucidated by extensive spectroscopic data analyses, whereas their absolute configurations were defined by electronic circular dichroism data. Ouratein D (4) inhibited in vitro the release of the pro-inflammatory cytokine CCL2 by lipopolysaccharide-stimulated THP-1 cells (IC50 of 3.1 ± 1.1 µM), whereas TNF and IL-1ß release were not reduced by any of the biflavanones. These findings show ouratein D (4) as a selective CCL2 inhibitor, which may have potential for the development of new anti-inflammatory agents to prevent or treat cardiovascular diseases.

Identification of a potent and selective gametocytocidal antimalarial agent from the stem barks of Lophira lanceolata.

Bioassay-guided fractionation of the organic extract obtained from stem barks of the African plant Lophira lanceolata has led to the isolation of seven biflavonoids, including the new α'-chlorolophirone E (5) and 5'-chlorolophirone D (6). Among the isolated compounds, the bichalcone lophirone E was identified as a potent gametocytocidal agent with an IC50 value in the nanomolar range and negligible cytotoxicity (selectivity index = 570). Lophirone E proved to be about 100 times more active against P. falciparum stage V gametocytes than on asexual blood stages, thus exhibiting a unique stage-specific activity profile. The isolation of structural analogues allowed to draw preliminary structure-activity relationships, identifying the critical positions on the chemical scaffold of lophirone E.

Chemical and Biological insights of Ouratea hexasperma (A. St.-Hil.) Baill.: a source of bioactive compounds with multifunctional properties.

The study aimed to evaluate in vitro antioxidant, anticholinesterase and antidiabetic properties of Ouratea hexasperma (A. St.-Hil.) Baill. The inflorescence methanol extract and the ethyl acetate fraction of leaves and stems reported the highest Relative Antioxidant Capacity Index (RACI), whereas the dichloromethane fraction of leaves was the best inhibitor of α-amylase and α-glucosidase. Trans-3-O-methyl-resveratrol-2-C-ß-glucoside, lithospermoside, 2,5-dimethoxy-p-benzoquinone, lup-20(30)-ene-3ß,28-diol, 7-O-methylgenistein, apigenin and luteolin and amentoflavone were isolated from O. hexasperma. Resveratrol derivative was isolated for the first time in Ochnaceae family. Luteolin, followed by apigenin, reported the highest Relative Antioxidant Capacity Index and they were also the best inhibitors of α-glucosidase enzyme.

The orofacial antinociceptive effect of Kaempferol-3-O-rutinoside, isolated from the plant Ouratea fieldingiana, on adult zebrafish (Danio rerio).

The aim of this study was to evaluate the antinociceptive effect of Kaempferol-3-O-rutinoside (KR), isolated from the plant Ouratea fieldingiana, on the orofacial nociception and possible mechanisms of action. Adult zebrafish (Danio rerio) were tested as a behavioral model to study formalin, glutamate, capsaicin, cinnamaldehyde and acidic saline-induced orofacial nociception, using as parameter the number of times the fish crossed the lines between the quadrants of a glass Petri dish during a specific time. Morphine was used as positive control. The effect of KR was tested for modulation by opioid (naloxone), nitrergic (L-NAME), TRPV1 (ruthenium red), TRPA1 (camphor) or ASIC (amiloride) antagonists. The effect of KR on zebrafish locomotor behavior was evaluated with the open field test. KR did not alter the fish's locomotor system and significantly reduced the orofacial nociceptive behavior induced by all noxious agents compared to the control group. The antinociceptive effect of KR was similar to morphine. All antagonists inhibited the antinociceptive effect of KR. KR has pharmacological potential for the treatment of acute orofacial pain and this effect is modulated by the opioid and nitrergic systems as well as TRPV1, TRPA1 and ASIC channels. These results can lead to the development of a new natural product for the treatment of orofacial pain and confirm the popular use of O. fieldingiana leaf for pain relief.

Efficacy of Lophira alata Leaf Extract and its Combination with Artesunate in Mice Prior Exposed to Plasmodium berghei.

Enhanced antimalarial activity of plant extracts used for treatment of malaria in endemic areas is attributed to partial immunity gained by prior infection. This suggests synergy between immunity and extract activity in treatment. Testing this hypothesis, rodent malaria was used to determine efficacy of Lophira alata leaf extracts in treating malaria in prior infected mice. One round of P. berghei infection and Pyrimethamine drug-cure was used to establish partial immunity in mice. Previously Exposed Mice (PEM) and Previously Unexposed Mice (PUM) mice challenged with P. berghei were used to determine influence of partial antimalarial immunity on efficacy of L. alata leaf extracts, administered alone or in combination with Artesunate (ART) in malaria treatment. There was a significant reduction in parasitemia in PEM when compared to PUM animals (P<0.001) irrespective of treatment regimen. Administration of L. alata combined with ART significantly reduced parasitemia (P<0.0032) and prolonged (P=0.0109) survival than when L. alata was administered alone in infected mice. These findings suggest that the action of L. alata in treating malaria infections in a murine model is enhanced by prior exposure to the malaria parasite. Thus the requirements of using plants in treating malaria in endemic populations may differ for those used in western systems, where trials are carried out with non-immune cohorts. Combining artemisinin derivatives and medicinal plants in malaria exposed populations may provide an alternative control measure in endemic regions and may justify the continued use of these plants by indigenous populations in treating malaria.

In Vitro Screening of Three Indian Medicinal Plants for Their Phytochemicals, Anticholinesterase, Antiglucosidase, Antioxidant, and Neuroprotective Effects.

Cooccurrence of Diabetes Mellitus and Alzheimer's disease in elder people prompts scientists to develop multitarget agents that combat causes and symptoms of both diseases simultaneously. In line with this modern paradigm and as a follow-up to our previous studies, the present study is designed to investigate the crude methanolic extracts and subsequent CHCl3, n-BuOH, and H2O fractions of Acalypha alnifolia, Pavetta indica, and Ochna obtusata for their inhibitory activities towards specific targets involved in AD and DM, namely, acetylcholinesterase, butyrylcholinesterase, and α-glucosidase (α-Glc). The methanolic extract and its derived chloroform fractions exhibited remarkable inhibitory capacities with IC50 values being found at the µg/mL level. Further studies on most active chloroform fractions presented a prominent ability to scavenge DPPH and ABTS reactive species and highest neuroprotective effect against H2O2 induced cell injury. Phytochemical analysis showed a large amount of phenolics, flavonoids, and terpenoids in active fractions. In conclusion, A. alnifolia, P. indica, and O. obtusata could be promising sources for the treatment of AD and DM since these fractions induced significant anticholinesterase, antidiabetic, antioxidant, and neuroprotection effects attributable to phenolic, flavonoid, and terpenoid contents and encourage further studies for development of multifunctional therapeutic agent for AD and DM dual therapy.

Phytochemical analysis and in vitro anthelmintic activity of Lophira lanceolata (Ochnaceae) on the bovine parasite Onchocerca ochengi and on drug resistant strains of the free-living nematode Caenorhabditis elegans.

BACKGROUND: Onchocerciasis is one of the tropical neglected diseases (NTDs) caused by the nematode Onchocerca volvulus. Control strategies currently in use rely on mass administration of ivermectin, which has marked activity against microfilariae. Furthermore, the development of resistance to ivermectin was observed. Since vaccine and safe macrofilaricidal treatment against onchocerciasis are still lacking, there is an urgent need to discover novel drugs. This study was undertaken to investigate the anthelmintic activity of Lophira lanceolata on the cattle parasite Onchocerca ochengi and the anthelmintic drug resistant strains of the free living nematode Caenorhabditis elegans and to determine the phytochemical profiles of the extracts and fractions of the plants. METHODS: Plant was extracted in ethanol or methanol-methylene chloride. O. ochengi, C. elegans wild-type and C. elegans drug resistant strains were cultured in RPMI-1640 and NGM-agar respectively. Drugs diluted in dimethylsulphoxide/RPMI or M9-Buffer were added in assays and monitored at 48 h and 72 h. Worm viability was determined by using the MTT/formazan colorimetric method. Polyphenol, tannin and flavonoid contents were determined by dosage of gallic acid and rutin. Acute oral toxicity was evaluated using Swiss albino mice. RESULTS: Ethanolic and methanolic-methylene chloride extracts killed O. ochengi with LC50 values of 9.76, 8.05, 6.39 µg/mL and 9.45, 7.95, 6.39 µg/mL respectively for leaves, trunk bark and root bark after 72 h. The lowest concentrations required to kill 50% of the wild-type of C. elegans were 1200 and 1890 µg/mL with ethanolic crude extract, 1000 and 2030 µg/mL with MeOH-CH2Cl2 for root bark and trunk bark of L. lanceolata, respectively after 72 h. Leave extracts of L. lanceolata are lethal to albendazole and ivermectin resistant strains of C. elegans after 72 h. Methanol/methylene chloride extracted more metabolites. Additionally, extracts could be considered relatively safe. CONCLUSION: Ethanolic and methanolic-methylene chloride crude extracts and fractions of L. lanceolata showed in vitro anthelmintic activity. The extracts and fractions contained polyphenols, tannins, flavonoids and saponins. The mechanism of action of this plant could be different from that of albendazole and ivermectin. These results confirm the use of L. lanceolata by traditional healers for the treatment of worm infections.

A Nitrile Glucoside and Biflavones from the Leaves of Campylospermum excavatum (Ochnaceae).

The study of the MeOH extract of the leaves of Campylospermum excavatum led to the isolation of a nitrile glucoside, named campyloside C (1) and an original derivative of ochnaflavone, 7-O-methylochnaflavone (2), along with three known biflavonoids, amentoflavone, sequoiaflavone, and sotetsuflavone (3 - 5). The linkage site of the sub-units of 2 was confirmed by chemical correlation, after semi-synthesis of a trimethoxylated derivative of ochnaflavone (2a). The structures of these compounds as well as their relative and absolute configurations were assigned by 1D- and 2D-NMR experiments, HR-ESI-MS and Electronic Circular Dichroism (ECD) calculations. A low-pass J filter HMBC experiment was performed in order to define the configuration of the double bond of 1. All of the biflavonoids were evaluated against protozoan parasites. Amentoflavone moderately inhibited the promastigote form of Leishmania infantum.

A new procyanidin B from Campylospermum zenkeri (Ochnaceae) and antiplasmodial activity of two derivatives of (±)-serotobenine.

Phytochemical investigation of the stem bark of Campylospermum zenkeri led to the isolation of five known compounds: (Z,Z)-9,12-octadecadienoic acid (1), serotobenine (2), agathisflavone (3), lophirone A (4) and lophirone F (5), together with a new derivative of procyanidin B, a catechin dimer named zenkerinol (6). Serotobenine (2) is structurally related to decursivine which shows moderate activity against D6 and W2 strains of Plasmodium falciparum. For a better understanding of structure-activity relationships, three new semi-synthetic derivatives of serotobenine (2) have been prepared. These are: serotobenine monopropionate (2a), serotobenine monopivalate (2b) and serotobenine cyclohexyl ether (2c) respectively. Two of them (2a) and (2b), were evaluated for their antiplasmodial activity against P. falciparum 3D7 strain in a parasite lactate-dehydrogenase (pLDH) assay. Compound 2b was more active than compound 2a based on their IC50 values (36.6 and 123 µM, respectively).

Chemical constituents of the leaves of Campylospermum elongatum.

The leaves of Campylospermum elongatum have furnished the cyano-glycoside (lithospermoside), nine isomeric biflavonoid derivatives among which five are I3-II6 linked (robustaflavone; 4'-O-methyl robustaflavone; 4',4″'-di-O-methyl robustaflavone; 7,4',4″-tri-O-methyl robustaflavone; 4',7″-di-O-methyl robustaflavone) and four I3-II8 linked (amentoflavone; 7-O-methyl amentoflavone; 7,7″-di-O-methyl amentoflavone; 7, 4',7″-tri-O-methyl amentoflavone) and a flavone glycoside, 4″-O-methyl-7-O-ß-d-galactosylapigenin. All structures were established from a complete spectroscopic analysis (MS, IR, 1D, and 2D NMR, including HSQC, HMBC, and NOESY) as well as by comparing the obtained spectroscopic data with literature. This is the first report on the characterization of 4'-O-methyl-7-O-ß-d-galactosylapigenin from the genus campylospermum and thus has important chemotaxonomic implications.

Anti-proliferative study and isolation of Ochnaflavone from the ethyl acetate-soluble fraction of Ochna kibbiensis Hutch & Dalziel.

Anti-proliferative activity of the ethyl acetate fractions of Ochna schweinfurthiana F. Hoffm. and Ochna kibbiensis Hutch. and Dalziel methanol leaf extracts were investigated against glioblastoma multiforme (GBM U-1242 MG) cell line. O. kibbiensis significantly (p < 0.001) and dose dependently (IC50 = 25.74 µg/mL) reduced cell count. At 125 µg/mL, O. kibbiensis extract reduced cell count by about 92% compared to the untreated control. On the other hand, at 125 µg/mL, O. schweinfurthiana extract reduced cell count only by 20%, indicating a much weaker activity (IC50 = 823.51 µg/mL). Following from the result obtained, ethyl acetate fraction of O. kibbiensis was subjected to chromatographic purification. This led to the isolation of ochnaflavone; the structure of the isolated compound was identified by analysis of its nuclear magnetic resonance (NMR) spectral data and comparison with data in the literature. Although the isolated ochnaflavone could not be tested for anti-proliferative activity due to insufficient quantity, the obtained results indicate the presence of bioactive anti-GBM principles in O. kibbiensis.

Neurobehavioural evaluation of Lophira alata (Ochnaceae) stem bark extract in mice.

BACKGROUND: Stem bark and leaves of Lophira alata (Family: Ochnaceae) have been used traditionally for their anti-psychotic, anti-convulsant and anxiolytic properties. Since no existing data was found on the neurobehavioural properties, this study was carried out to evaluate some neurobehavioural properties of the aqueous extract of the stem bark of L. alata in animal models. METHODS: The oral mean lethal dose (LD50) of the extract was estimated, and preliminary phytochemical screening was conducted. Lophira alata extract (200, 400 and 800 mg/kg, p.o.) was investigated for antidepressant effect using the forced swim and tail suspension tests, and the anxiolytic potential was assessed using the stair case and hole board tests. Pentylenetetrazole-induced convulsion test was used to investigate the anticonvulsant potential of the extract. RESULTS: The LD50 was estimated to be >5000 mg/kg. Oral administration of L. alata extract produced a significant (p<0.05) non-dose-dependent decrease in the period of immobility in both the forced swim and tail suspension tests. While a significant decrease (p<0.05) in episodes of grooming was recorded in the staircase test, the number of head dips was not significantly reduced (p>0.05) in the hole board test. In the pentylenetetrazole-induced convulsion, a non-dose-dependent increase in onset of tonic-clonic seizures and protection from death was recorded. CONCLUSIONS: The results obtained suggest that the aqueous stem bark extract of L. alata possesses neurobehavioural properties which may account for its use in ethnomedicine.

Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana.

Seven flavonoids, hemerocallone (1), 6,7-dimethoxy-3',4'-dimethoxyisoflavone (2), amentoflavone (4), agathisflavone (6), cupressuflavone (8), robustaflavone (9) and epicatechin (10), together with three other compounds, lithospermoside (3), ß-D-fructofuranosyl-α-D-glucopyranoside (5) and 3ß-O-D-glucopyranosyl-ß-stigmasterol (7), were isolated from the ethyl acetate extract of the stem bark of Ochna schweinfurthiana F. Hoffm. All the compounds were characterised by spectroscopic and mass spectrometric methods, and by comparison with literature data. Cytotoxicity of the extracts and compounds against cervical adenocarcinoma (HeLa) cells was evaluated by MTT assay. Compounds 4 and 6 exhibited good cytotoxic activity, with IC50 values of 20.7 and 10.0 µM, respectively.

Estudio fitoquímico de plantas utilizadas en el control de la diabetes mellitus y evaluación de la actividad biológica sobre glucosa-6-fosfatasa de los metabolitos aislados y productos sintetizados / Phytochemical study of plants used in the control of diabetes mellitus and evaluation of the biological activity on glucose-6-phosphatase of isolated metabolites and synthesized products

La diabetes mellitus afecta a muchas personas alrededor del mundo, por lo que la comunidad científica está interesada en la búsqueda de nuevas drogas de origen sintético o natural para el tratamiento de la misma. En el presente trabajo se utilizaron cuatro plantas empleadas tradicionalmente en el tratamiento empírico de la diabetes y se realizó la síntesis total de los productos naturales α- yß- pentagaloilglucosa, ácido elágico y sus análogos. Las plantas estudiadas provienen de los géneros: Ouratea polyantha Engl. (Ochnaceae), Capraria biflora L. (Schrophulariaceae), Cassia fruticosa Mill. (Fabaceae) y Ruellia tuberosa L. (Acanthaceae). De la planta O. polyantha Engl., se aisló por HSCCC, e identificó por técnicas espectroscópicas el flavonoide rutina (OpC-4), la biflavona agathisflavona (OpD-5, OpB-M1), el ácido 4-hidroxibenzóico (OpD-10) y un nuevo megastigmano identificado como (6R,9S)-6'-(4''-hidroxibenzoil)-roseósido (OpD-9). Adicionalmente, se obtuvieron fracciones enriquecidas en lupeol y ß-sitosterol (OpBHex-FrCHCl3), agathisflavona (OpA, OpG) y rutina (OpA, OpC, OpG, OpH) las cuales fueron identificadas por CCF y HPLC comparando con muestras auténticas. Se evaluó el contenido de flavonoides totales como % de rutina en las fracciones OpC, OpG y OpH, por ensayos colorimétricos con AlCl3, obteniendo valores de: 7,08 ± 0,04; 31,9 ± 1,0; y 12,4 ± 0,3 %, respectivamente. De la planta C. fruticosa Mill., se aisló e identificó, por cromatografía flash y técnicas espectroscópicas el ester esteriodal ß-sitosterol palmitato•1/2•H2O (CfRS-3) y los flavonoides glicosilados kaempferol 3-O-rutinósido (nicotiflorin, CfH-1) y kaempferol 3-O-(2''-ramnosil)rutinósido (clitorin, CfH-2). Adicionalmente, se obtuvieron fracciones enriquecidas ß-sitosterol (CfB), y en los flavonoides nicotiflorin y clitorin (CfF, CfYY). De la planta C. biflora L., se aisló e identificó el glicosido manitol (CbE), el cual fue purificado por múltiples procesos de recristalización (CbM-2) y caracterizado por sus propiedades físicas y por la obtención de su derivado semisintético hexaacetilmanitol (CbM-2Ac). Adicionalmente, se obtuvieron fracciones enriquecidas en ß-sitosterol (CbI-FrCHCl3), azúcares (CbG, CbO), porfirinas tipo feoforbido-a (CbK y CbL) y terpenos aromáticos (CbK, CbF, CbN, CbP). De la planta R. tuberosa L., se obtuvieron fracciones enriquecidas en lupeol, betulina y ß-sitosterol (RtB, RtR-1, RtR-K), azúcares (RtI, RtR-G) polifenoles (RtJ, RtQac, RtSac, RtR-Mac, RtR-Nac) y terpenos aromáticos (RtQorg, RtSorg, RtR-Morg, RtR-Norg). En RtR-K se cuantificó por densitometría óptica el contenido porcentual de: lupeol 37,3 ± 0,8; ß-sitosterol 15,6 ± 0,6 y betulina (4,3 ± 0,3) % respectivamente. Los flavonoides aislados agathisflavona, nicotiflorin y clitorin mostraron inhibición significativa sobre el sistema enzimático G-6-Pasa microsomal cuyos valores fueron 63, 60 y 46 % respectivamente. Por otra parte, las fracciones terpenoidal (RtR-K) y porfirínicas (CbK y CbL) presentaron una inhibición moderada sobre la G-6-Pasa con 45, 25 y 27% respectivamente. Entre los productos sintetizados, los anómeros α- y ß-pentaacilglucosa (PAG, PBG y PGG-Bn) no presentaron actividad biológica significativa (<10%), lo cual indica claramente que el grupo galoilo es fundamental para la actividad biológica asociada a los taninos hidrolizables α-PGG y ß-PGG. A concentraciones finales de 50 µM, estos compuestos presentaron un porcentaje de inhibición de 77 y 79 % respectivamente con una significancia estadística importante (p<0,00006). Por otra parte, el ácido elágico (AE) sintetizado presentó un porcentaje de inhibición de 63% cuyo IC50 fue 76,50 µM, su derivado acetilado (AAcE) mostro un IC50 73,5 µM, mientras que, el derivado alquilico (AMeE) fue inactivo frente a la G-6-Pasa. Adicionalmente, AE y AAcE no mostraron actividad inhibitoria de la absorción intestinal de glucosa.