Indonesian medicinal plants. XIX. 1) Chemical structures of four additional resin-glycosides, mammosides A, B, H1, and H2, from the tuber of Merremia mammosa (Convolvulaceae)

Research Progression of the Genus Merremia: A Comprehensive Review on the Nutritional Value, Ethnomedicinal Uses, Phytochemistry, Pharmacology, and Toxicity

The genus Merremia Dennst. ex Endl. (Convolvulaceae) is a rich source of structurally diverse phytochemicals with therapeutic relevance. This review presents the first comprehensive, up-to-date information and research progression on the nutritional value, ethnomedicinal uses, phytochemistry, pharmacological activities, and toxicity of the genus Merremia. Using the key search term “Merremia”, relevant documents and information were retrieved from electronic databases. Relevant documents were uploaded in RStudio with installed bibliometric software packages and used for data retrieval, tabulation, and network visualization. Bibliometric analysis revealed that ca. 55% of the studies related to Merremia were published in the last decade, which can be grouped into four thematic areas: (i) drug formulation, (ii) taxonomy, (iii) chemical analysis, and (iv) treatment of diseases. Ethnomedicinal uses, phytochemistry, and biological activities studies showed that species in the genus are promising medicinal plants with various pharmaceutical potentials. However, clinical studies to validate the efficacy of the reported bioactivities and the mechanisms underlying the various activities are lacking and should constitute a future research focus. Additionally, reports on the nutritional and antinutritional constituents of Merremia species revealed that the species meet high nutritional quality criteria for animals and are therefore suitable for inclusion in livestock diets. The few available investigations on toxicity indicated that most Merremia species are safe for human and animal use but not with prolonged chronic administration.

Gel formulations of Merremia mammosa (Lour.) accelerated wound healing of the wound in diabetic rats

Background and aim

The treatment of diabetic ulcers is difficult because of defective blood vessels and frequent co-occurrence of bacterial infections. In a previous study, we found a water fraction of Merremia mammosa (Lour.) (Mm(Lour.)) had beneficial effects on wound healing in diabetic rats. This study aimed to evaluate the influence of different gelling agents added to Mm(Lour.) water fraction gel on wound healing treatment in diabetic rats.

Experimental procedure

Diabetic Wistar rats were divided into the following five groups: 1. positive control (Neomycin Sulfate 0.5% and Placenta Extract 10%), 2. negative control (distilled water), and 10% water fraction of Mm(Lour.) extract in 3. HPMC, 4. Carbopol, and 5. CMC Na gelling agents. The wound was made by the Morton method and treatment applied every other day for 25 days, then the wound healing process was observed. Data were observed and analysed using appropriate statistic tools.

Results

Histopathology observation, VEGF expression and hydroxyproline levels showed a significant acceleration of wound healing in all treatment groups compared to the negative control group. This study showed all of Mm(Lour.) gel formulations could restore the delayed healing process on wound in diabetic rats and were equally effective in accelerating wound healing. CMC Na was the most preferable because it did not irritate.

Conclusion

The results suggest that Mm(Lour.) water fraction in CMC Na gelling agent provided an option to be developed as a topical drug on diabetic wound healing treatment, showed by enhancement of collagen synthesis and angiogenesis.

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Merremia mammosa (Lour.) gel accelerated wound healing in the diabetic rat model.

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Negative-control and each other groups had significant different healing.

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Positive-control and treatment groups had insignificant different healing.

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The safest and suggested gelling agent as a topical drug was CMC Na.

Panitins A-G: Coumarin derivatives from Murraya paniculata from Guangxi Province, China show variable NO inhibitory activity

Seven previously undescribed coumarin derivatives, panitins A‒G, an ethoxylated artifact, and 34 known analogues, were isolated from the roots of Murraya paniculata. Their structures were elucidated on the basis of comprehensive analysis of 1D and 2D NMR and HRMS spectroscopic data, and comparison with the data reported in literature. The absolute configurations of undescribed compounds were assigned via comparison of the specific rotation, Mosher's method, exciton chiral method, and comparison of calculated and experimental ECD data. Panitin D, trans-dehydroosthol, and exotimarin I showed potent inhibition against LPS-induced NO production in BV-2 microglial cells with IC₅₀ values of 19.6 ± 2.3, 12.4 ± 0.9, and 26.9 ± 0.8 μM, respectively.

Resin glycosides from Ipomoea wolcottiana as modulators of the multidrug resistance phenotype in vitro

Recycling liquid chromatography was used for the isolation and purification of resin glycosides from the CHCl3-soluble extracts prepared using flowers of Ipomoea wolcottiana Rose var. wolcottiana. Bioassay-guided fractionation, using modulation of both antibiotic activity against multidrug-resistant strains of Gram-negative bacteria and vinblastine susceptibility in breast carcinoma cells, was used to isolate the active glycolipids as modulators of the multidrug resistance phenotype. An ester-type dimer, wolcottine I, one tetra- and three pentasaccharides, wolcottinosides I-IV, in addition to the known intrapilosin VII, were characterized by NMR spectroscopy and mass spectrometry. In vitro assays established that none of these metabolites displayed antibacterial activity (MIC>512 μg/mL) against multidrug-resistant strains of Escherichia coli, and two nosocomial pathogens: Salmonella enterica serovar Typhi and Shigella flexneri; however, when tested (25 μg/mL) in combination with tetracycline, kanamycin or chloramphenicol, they exerted a potentiation effect of the antibiotic susceptibility up to eightfold (64 μg/mL from 512 μg/mL). It was also determined that these non-cytotoxic (CI50>8.68 μM) agents modulated vinblastine susceptibility at 25 μg/mL in MFC-7/Vin(+) cells with a reversal factor (RFMCF-7/Vin(+)) of 2-130 fold.

Cytotoxic resin glycosides from Ipomoea aquatica and their effects on intracellular Ca2+ concentrations

Eleven new resin glycosides, aquaterins I-XI (1-11), were isolated from the whole plants of Ipomoea aquatica. The structures of 1-11 were elucidated by a combination of spectroscopic and chemical methods. They were found to be partially acylated tetra- or pentasaccharides derived from simonic acid B and operculinic acids A and C. The site of the aglycone macrolactonization was placed at C-2 or C-3 of the second saccharide moiety, while the two acylating residues could be located at C-2 (or C-3) of the second rhamnose unit and at C-4 (or C-3) on the third rhamnose moiety. All compounds were evaluated for cytotoxicity against a small panel of human cancer cell lines. Compound 4 exhibited the most potent activity against HepG2 cells with an IC50 value of 2.4 μM. Cell cycle analysis revealed 4 to inhibit the proliferation of HepG2 cells via G0/G1 arrest and apoptosis induction. In addition, compounds 1-4, 7, 9, and 10 were found to elevate Ca(2+) in HepG2 cells, which might be involved in the regulation of the cytotoxic activities observed.

Resin glycosides from the yellow-skinned variety of sweet potato (Ipomoea batatas)

Native to tropical America, Ipomoea batatas has been cultivated for over 5000 years in Mexico. The yellow-skinned tuber crop variety, with an orange flesh, has a higher nutritional value than potato. Raw sweet potato can cause a purge due to its resin glycoside content. Purification of the chloroform-soluble resin glycosides from the roots of this variety was accomplished by preparative-scale HPLC, which allowed for the collection of six oligosaccharides, batatin VII (1) and batatinosides VII-IX (2-4), all of novel structure, together with the known resin glycosides pescaprein I and batatinoside IV. High-field NMR spectroscopy and FAB mass spectrometry were used to characterize each structure, identifying operculinic acid A for compounds 2 and 4, and simonic acid B for 3, as their pentasaccharide glycosidic cores. Batatin VII (1) represents a dimer of the know batatinoside IV, consisting of two units of simonic acid B.

Batatins III-VI, glycolipid ester-type dimers from Ipomoea batatas

Batatins III-VI (1-4), glycolipid ester-type dimers, were isolated from the tuberous roots of sweet potato (Ipomoea batatas) using recycle high performance liquid chromatography. Their structures were characterized by means of several high-resolution NMR and mass spectrometry techniques. These compounds are the first examples of ester-type dimers which consist of two units of the heterotetrasaccharide operculinic acid C. Each unit was esterified by a different amount and type of acid residues: (2S)-methylbutanoic, cinnamic, decanoic (capric) and dodecanoic (lauric) acids. Batatins III-VI (1-4) are an example of the presence of a large number of resin glycoside congeners in each morning glory species caused by partial acylation of their constitutive saccharide cores.

Pentasaccharide resin glycosides from Ipomoea pes-caprae

Pescapreins XXI-XXX (1-10), pentasaccharide resin glycosides, together with the known pescapreins I-IV and stoloniferin III were isolated from the aerial parts of Ipomoea pes-caprae (beach morning-glory). The pescapreins are macrolactones of simonic acid B, partially esterified with different fatty acids. The lactonization site of the aglycone, jalapinolic acid, was located at C-2 or C-3 of the second saccharide moiety. Their structures were established by a combination of spectroscopic and chemical methods. Compounds 1-10 were evaluated for their potential to modulate multidrug resistance in the human breast cancer cell line MCF-7/ADR. The combined use of these new compounds at a concentration of 5 μg/mL increased the cytotoxicity of doxorubicin by 1.5-3.7-fold.

Macrocyclic substructure of tricolorin A – The first crystal structure of a resin glycoside

The structure of a tricolorin A derivative (11S)-11-[[4,6-O-benzylidene-β-D-glucopyranosyl-(1 → 2)-3,4-O-isopropylidene-β-D-fucopyranosyl]oxy]hexadecanoic acid 3gluc-lactone 2, a member of the resin glycosides, has been determined. This crystal structure is the first example for this class of natural products. At 100 K the lattice parameters in monoclinic space group P21 are: a = 22.502 (5)Å, b = 17.339( 4)Å, c= 25.011( 5)Å, β= 92.49(3)°, V = 9749(3)Å3 , Z = 10. M = 705.67, ρ= 1.202 Mg m -3 , μ = 0.087 mm-1 , F (000)= 3824. The five crystallographically independent molecules show upon superpositioning the expected preservation of the glycosidic link geometry, however the alkyl part of the macrocyclic ring expresses a larger degree of freedom while conserving gauche and anti conformations in six of nine torsion angles.

Astonishing diversity of natural surfactants: 2. Polyether glycosidic ionophores and macrocyclic glycosides

Polyether glycosidic ionophores and macrocyclic glycosides are of great interest, especially for the medicinal and pharmaceutical industries. These biologically active natural surfactants are good prospects for the future chemical preparation of compounds useful as antibiotics, anticancer agents, or in industry. More than 300 interesting and unusual natural surfactants are described in this review article, including their chemical structures and biological activities.

Stoloniferins VIII-XII, resin glycosides, from Ipomoea stolonifera

Five new ether-soluble resin glycosides were isolated from whole plants of Ipomoea stolonifera. Their structures have been determined on the basis of chemical and spectral data. Similar to the resin glycosides previously isolated, all of them are monomers of a jalapinolic acid tetra- or penta-glycoside in which the sugar moiety is partially acylated by organic acids and also combined with the carboxy group of the aglycone to form a macrocyclic ester structure.