New methyl threonolactones and pyroglutamates of Spilanthes acmella

[Objective] Spilanthes acmella is a medicinal plant that distributed in the tropical and subtropical regions with rich source of therapeutic and medicinal constituents. The main constituents, "spilanthol” and “ acmellonate”, are used to reduce the pain associated with toothaches and induce saliva secretion. It is also used traditionally as treatment of rheumatism, tongue paralysis, antipyretic, sore throat, and gum infections [1]. It contains phytosterols, essential oils, sesquiterpenes, α and β-bisabolenes and cadinenes, flavonoid glucoside and a mixture of long chain hydrocarbons. In recent years, other bioactive metabolites have been isolated as vanillic acid, trans-ferulic acid, trans-isofcrulic acid, scopolelin, 3-acetylaleuritolic acid and β-sitostenone[2], [Methods] The aerial parts of Spilanthes acmella were collected in Purwodadi, Indonesia, then extracted with methanol. The obtained methanol extract was concentrated and partitioned with n-hexane, ethyl acetate, and 1-butanol. [Results] On investigation of the 1-butanol layer of this plant, a new methyl threonolactone glucoside (1), a new methyl threonolactone fructofuranoside (2) and two new pyroglutamates (3, 4) along with 2-C-methyl-D-threono-1,4-lactone (5), 2-deoxy-D-ribono-1,4-lactone (6), methylpyroglutamate (7), dendranthemoside A (8), dendranthemoside B (9), ampelopsisionoside (10),icariside B2 (11), benzyl-α-L-arabinopyranosyl-( l-6)-β-D-glucopyranoside (12) and chicoriin (13) were isolated by various chromatographic techniques such as silica gel, ODS column chromatography and HPLC. The structures of these compounds were determined as follows by spectrometric analysis (UV, IR, ID- and 2D-NMR, and HR-ESI-MS)

New Isolinariins C, D and E, Flavonoid Glycosides from Linaria japonica

Three new flavonoid glycosides named isolinariins C, D and E (1–3), two known flavonoid glycosides (4,5) and three known flavonoids (6–8) were isolated from the whole plant of Linaria japonica. The structures of these compounds were determined mainly by spectroscopic analyses. The bioactivities of these isolated compounds were evaluated for their inhibitory activities against human cell line A549, collagenase, and advanced glycation end product (AGE) formation. Among the isolated compounds, isolinariins C, D and E (1, 2 and 3) showed inhibition toward AGE formation (IC50 values of 34.8, 35.0 and 19.5 µM, respectively). And linariin (4), pectolinarin (5) and luteolin (8) were found to be active against collagenase with IC50 values of 79.4, 78.6 and 40.5 µM, respectively, without significant cytotoxicity at these concentrations

Understanding the Biosynthesis of Paxisterol in Lichen-Derived Penicillium aurantiacobrunneum for Production of Fluorinated Derivatives

The U.S. endemic lichen (Niebla homalea)-derived Penicillium aurantiacobrunneum produced a cytotoxic paxisterol derivative named auransterol (2) and epi-citreoviridin (6). Feeding assay using 13C1-labelled sodium acetate not only produced C-13-labelled paxisterol but also confirmed the biosynthetic origin of the compound. The fluorination of bioactive compounds is known to improve pharmacological and pharmacokinetic effects. Our attempt to incorporate the fluorine atom in paxisterol and its derivatives using the fluorinated precursor sodium monofluoroacetate resulted in the isolation of 7-monofluoroacetyl paxisterol (7). The performed culture experiment, as well as the isolation and structure elucidation of the new fluorinated paxisterol, is discussed herein

New flavonoid glycosides from Linaria Japonica

[Objective] Linaria japonica (Scrophulariaceae) is a perennial herb (which grows on the sandy place along seashores in Japan with elliptic and fleshy leaves. The whole plant extract is used as a folk medicine due to its diuretic and purgative pharmacological activities. In our previous phytochemical investigations on this plant, several new flavonoid, iridoid and megastigmane glycosides were isolated from 1-butanol fraction. In this study, further phytochemical investigation was performed on non-polar fraction, i.e. mixture of hexane-ethyl acetate soluble fraction of this plant. [Methods] Whole plants of Linaria japonica were collected in Tottori prefecture. The air-dried plants were extracted with methanol two times. The obtained methanol extract was concentrated and suspended in water, then partitioned with n-hexane, ethyl acetate, and 1-butanol. [Results] On investigation of the mixture of hexane-ethyl acetate layer of the plant, three new flavonoid glycosides (1-3) and five new diterpenes (4-8) along with five known flavonoid glycosides (9-10), three known flavonoids (11-13) and two known diterpenes (14, 15) were isolated by various chromatographic techniques such as silica gel, ODS column chromatography and HPLC. The structures of these compounds were determined as follows by spectrometric analysis (UV, IR, ID- and 2D-NMR, and HR-ESI MS)

New cis-ent-clerodanes from Linaria Japonica

Five new cis-ent-clerodanes, linarenones A–E (1–5) and two known compounds (6 and 7) were isolated from whole plant of Linaria japonica. The structures of these compounds were determined by various spectroscopic analyses (UV, IR, HR–ESI–MS, 1D and 2D NMR). The absolute configuration of five new diterpenoids was confirmed by circular dichroism (CD) analysis and chemical conversion. Cytotoxicity of the isolated compounds against A549 cell lines and Leishmania major were evaluated. The new cis-entclerodane 3 was found to be moderately active against A549 cell lines, and new cis-ent-clerodanes 1,6 and desacetyl-linarienone (7) were active against L. major

New Methyl Threonolactones and Pyroglutamates of Spilanthes acmella (L.) L. and Their Bone Formation Activities

In our continuing research for bioactive constituents from natural resources, a new methyl threonolactone glucopyranoside (1), a new methyl threonolactone fructofuranoside (2), 2 new pyroglutamates (3 and 4), and 10 known compounds (5–14) were isolated from the whole plant of Spilanthes acmella (L.) L. The structures of these compounds were determined based on various spectroscopic and chemical analyses. All of the isolated compounds were evaluated on bone formation parameters, such as ALP (alkaline phosphatase) and mineralization stimulatory activities of MC3T3-E1 cell lines. The results showed that the new compound, 1,3-butanediol 3-pyroglutamate (4), 2-deoxy-d-ribono-1,4-lactone (6), methyl pyroglutamate (7), ampelopsisionoside (10), icariside B1 (11), and benzyl α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside (12) stimulated both ALP and mineralization activities

New Methyl Threonolactones and Pyroglutamates of Spilanthes acmella (L.) L. and Their Bone Formation Activities

In our continuing research for bioactive constituents from natural resources, a new methyl threonolactone glucopyranoside (1), a new methyl threonolactone fructofuranoside (2), 2 new pyroglutamates (3 and 4), and 10 known compounds (5–14) were isolated from the whole plant of Spilanthes acmella (L.) L. The structures of these compounds were determined based on various spectroscopic and chemical analyses. All of the isolated compounds were evaluated on bone formation parameters, such as ALP (alkaline phosphatase) and mineralization stimulatory activities of MC3T3-E1 cell lines. The results showed that the new compound, 1,3-butanediol 3-pyroglutamate (4), 2-deoxy-d-ribono-1,4-lactone (6), methyl pyroglutamate (7), ampelopsisionoside (10), icariside B1 (11), and benzyl α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside (12) stimulated both ALP and mineralization activities

Four New Flavonoids Isolated from the Aerial Parts of Cadaba rotundifolia Forssk. (Qadab)

Cadaba rotundifolia (Forssk.) (family: Capparaceae; common name: Qadab) is one of four species that grow in the Red Sea costal region in the Kingdom of Saudi Arabia. The roots and leaves of C. rotundifolia is traditionally used to treat tumors and abscesses in Sudan. A previous phytochemical study of the roots yielded a quaternary alkaloid, but no report on chemical constituents of the aerial parts of the C. rotundifolia growing in Saudi Arabia has been issued so far. Oxidative stress and advanced glycation end products (AGEs) are thought as causal factors in many degenerative diseases, such as Alzheimer’s disease, diabetes, atherosclerosis and aging. In this study, a total of twenty compounds, including four previously undescribed acylated kaempferol glucosides, were isolated from the aerial parts of C. rotundifolia collected in Saudi Arabia. These new compounds were identified as kaempferol 3-O-[2-O-(trans-feruloyl)-3-O-β-d-glucopyranosyl]-β-d-glucopyranoside (1), kaempferol 3-O-β-neohesperidoside-7-O-[2-O-(cis-p-coumaroyl)-3-O-β-d-glucopyranosyl]-β-d-glucopyranoside (2), kaempferol 3-O-[2,6-di-O-α-l-rhamnopyranosyl]-β-d-glucopyranoside-7-O-[6-O-(trans-feruloyl)]-β-d-glucopyranoside (3) and kaempferol 3-O-[2,6-di-O-α-l-rhamnopyranosyl]-β-d-glucopyranoside-7-O-[6-O-(trans-p-coumaroyl)]-β-d-glucopyranoside (4). Their structures were established based on UV-visible, 1D, 2D NMR, and HR-ESI-MS analyses. Of the assayed compounds, 17 and 18 showed potent radical scavenging activity with IC50 values of 14.5 and 11.7 µM, respectively, and inhibitory activity toward AGEs together with compound 7 with IC50 values 96.5, 34.9 and 85.5 µM, respectively

Potent growth inhibitory activity of platencin towards multi-drug-resistant and extensively drug-resistant Mycobacterium tuberculosis

The potent antimycobacterial activity of (±)-platencin is reported. Complete inhibition of Mycobacterium smegmatis growth was observed at MICs of 0.5 μg mL−1 and 0.3 μg mL−1 under aerobic and hypoxic conditions, respectively. Notably, the compound exhibited potent bacteriostatic activities towards Mycobacterium tuberculosis H37Rv (MIC = 2 μg mL−1), multi-drug-resistant M. tuberculosis (MIC = 1 μg mL−1), and extensively drug-resistant M. tuberculosis (MIC = 1 μg mL−1). An overexpression study of the transformants of M. smegmatis revealed that platencin selectively targeted Mt-KasB and modestly inhibited Mt-KasA and Mt-FabH

Firmosides A and B: two new sucrose ferulates from the aerial parts of Silene firma and evaluation of radical scavenging activities

Two new tri-ferulates of sucrose, firmosides A and B (1 and 2, respectively), together with 18 known compounds (3–20), were isolated from the aerial parts of Silene firma. The structures of the isolated compounds were elucidated by various spectroscopic methods, including 1D, 2D NMR, and high-resolution electro-spray ionization–mass spectrometry (HR-ESI–MS). All the isolated compounds were evaluated for their free radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. As a result, two new compounds (1, 2) and 11 demonstrated significant radical scavenging activity, implying the usefulness as antioxidant agents