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The skin plays various crucial biological functions and gradually degenerates due to the process of skin aging. Hence, the development of new ingredients for delaying or even reversing skin aging is an essential subject that needs to be addressed. Our screening effort for anti-skin aging ingredients has led to the discovery that Sideritis scardica extract (SSE) possesses collagenase inhibition, advanced glycation end product (AGE) formation inhibition, antioxidative, and antiallergic activities, as well as ultraviolet B (UVB)-induced matrix metalloproteinase-1 (MMP-1) expression inhibition activity. However, the effect of S. scardica, commonly known as a mountain herb, on skin aging is unknown and needs additional study. Further studies on SSE have led to the isolation of 3 flavonoids with an uncommon 8-hydroxyl moiety, isoscutellarein (1), 4′- O -methylhypolaetin (2), and 4′- O -methylisoscutellarein (3). Biological evaluations also revealed that 1 - 3 possess SSE collagenase inhibition, AGE formation inhibition, antioxidative, and antiallergic activities, while 3 was identified to possess SSE UVB-induced MMP-1 expression inhibition activity. Moreover, the AGE formation inhibition activity and antiallergic activity of 1 - 3 were speculated to be derived from their antioxidative activity, while direct inhibition of the collagenase enzyme led to their observed collagenase inhibition activity. Regarding the inhibition activity of 1 - 3 on UVB-induced MMP-1 expression, further studies are necessary to reveal their possible mechanism of action. Collectively, the biological activities of SSE and the isolated flavonoids 1 - 3 highlight the potential of S. scardica to be further developed as an agent to delay or reverse skin aging. [ABSTRACT FROM AUTHOR]

Jatropha multifida is a medicinal plant that belongs to the Euphorbiaceae family. Our investigation revealed that the chloroform extract of J. multifida stems showed anti-melanin deposition activity against α-melanocyte stimulating hormone (α-MSH)- and 3-isobutyl-1-methylxanthine (IBMX)-induced melanogenesis in the mouse melanoma cell line (B16-F10). Further fractionation and purification of the major constituents led to the isolation of two coumarins (1 and 2) and seven known lignoids (3–9). All isolated compounds exhibited anti-melanin deposition activities against the mouse melanoma cell line (B16-F10) with IC50 values ranging from 37.5 to 560.1 µM, without any cytotoxicity even at high concentrations, except for 8. Further mechanistic studies suggested that 9 downregulated tyrosinase mRNA expression, while the anti-melanin deposition activities of 4 and 8 appeared to be unrelated to tyrosinase inhibition and the downregulated expression of the key melanogenesis-associated mRNAs. These results suggested that J. multifida could possess potent skin whitening ingredients. [ABSTRACT FROM AUTHOR]

A new alkylbenzoquinone named embeliquinone (1) together with five known compounds, lupeol (2), 3-O-[6′-O-palmitoyl-β-d-glucosyl]-spinasta-7,22(23)-diene (3), quercetin (4), (2S,3S,4R,8E)-2-[(2′R)-2′-hydroxy-heneicosanoylamino]-heneicosane-1,3,4-triol-8-ene (5), and β-sitosterol-3-O-β-d-glucopyranoside (6) were isolated from the MeOH leaf extract of Embelia rowlandii by using repeated open column chromatography techniques. The structure of the new compound was characterized by analyses of 1D- and 2D-NMR, and MS data. Embeliquinone (1) had moderate anti-cell proliferation activity against A549 cell line with the IC50 value of 21.8 μM. In addition, 1 exhibited weak antibacterial activities against Klebsiella pneumoniae and Staphylococcus aureus with an MIC value of 206.0 μM in both cases. [ABSTRACT FROM AUTHOR]

Picrasma javanica Blume (Simaroubaceae) is a medium-sized tree that is distributed widely in tropical Asia. In our previous study, we isolated quassinoids from P. javanica bark collected in Myanmar, and reported their antiproliferative activities. In our ongoing research for the discovery of bioactive compounds from Myanmar medicinal plants, two new quassinoids, (16R)-methoxyjavanicin B (1) and (16S)-methoxyjavanicin B (2), along with seven known compounds (3–9), were isolated during the phytochemical investigation of the CHCl3 soluble portion of the MeOH extract of P. javanica wood. The structures of the new compounds were elucidated by analyses of their spectroscopic data (1D- and 2D-NMR, HRESIMS, and CD). A cytotoxicity assay revealed that compound 8 showed moderate activities against all tested cancer cell lines, the human lung (A549), breast (MCF7), and cervical (HeLa), and the normal fibroblast cell line, with IC50 values ranging from 48.6 to 65.9 μM. Furthermore, the antibacterial assay demonstrated that 1 and 2 had the highest activities (MIC value of 1.6 μM each), followed by 5 and 3 (MIC values of 3.1 and 6.3 μM, respectively) against the Gram-positive bacterium B. subtilis. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The phytochemicals of a medicinal plant, Eriosema robustum, were re-investigated. • A new coumaronochromone (1) and a new furanoflavone (2) were isolated from the plant. • The structures of 1 and 2 were characterized by NMR and HR-ESIMS. • 1 and 2 exhibited weak activity with MICs > 150 μg/mL against bacteria and fungi. • 1 (IC 50 340.3 ± 0.1 μM) and 2 (IC 50 524.6 ± 0.1 μM) had weak antioxidant activity. Abstract A new coumaronochromone, eriocoumaronochromone (1), and a new alkanoyl-dihydrofuranoflavone glycoside, robusflavone C (2), as well as seven known compounds, 6-prenylpinocembrin (3), desmoxyphyllin A (4), prutin (5), genistein (6), vitexin (7), kaempferol (8), and p -hydroxy benzoic acid (9), were obtained after phytochemical re-investigation of the EtOAc-soluble portion from the EtOH extract of the twigs of Eriosema robustum. The structures of the new compounds were elucidated by analyses of their spectroscopic data (1D- and 2D- NMR, and HR-ESIMS) and chemical conversion. 1 and 2 exhibited weak antioxidant activity with IC 50 340.3 ± 0.1 and 524.6 ± 0.1 μM in 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay, and possessed weak antimicrobial activity with MICs > 150 μg/mL against Bacillus subtilis , Staphylococcus aureus , Klebsiella pneumoniae , Escherichia coli, Candida albicans , and Saccharomyces cerevisiae. [ABSTRACT FROM AUTHOR]

Abstract: AmbP1 is a cyanobacterial aromatic prenyltransferase and a dedicated synthase for (R)‐3‐geranyl‐3‐isocyanovinyl indolenine (2), the biogenetic precursor for hapalindole‐type alkaloids. The regioselective geranylation of cis‐indolyl vinyl isonitrile (1) by the standalone AmbP1 to give 2 has been shown to require a magnesium ion (Mg2+) to suppress the formation of cis‐2‐geranylindolyl vinyl isonitrile (3). Here, we report high‐resolution crystal structures of AmbP1 in complex with 1 and geranyl S‐thiodiphosphate (GSPP) in the presence and absence of a Mg2+ effector. The comparative study of these structures revealed a unique allosteric binding site for Mg2+ that modulates the conformation of 1 in the active site of AmbP1 for its selective geranylation. This work defines the structural basis for AmbP1 catalysis in the biogenesis of hapalindole‐type alkaloids and provides the first atomic‐level insight to the allosteric regulation of prenyltransferases. [ABSTRACT FROM AUTHOR]

Marine organisms such as marine sponges and soft corals are valuable sources of pharmacologically active secondary metabolites. In our ongoing research on the discovery of new secondary metabolites from marine organisms, two new pyrrolo-2-aminoimidazoles, clathriroles A (1) and B (2), were isolated from the water-soluble portion prepared from the methanol and acetone (2:1) extract of the marine sponge, Clathria prolifera, collected in Myanmar. The chemical structures of the isolated compounds were determined using extensive spectroscopic techniques, including NMR, HRESIMS, IR, and optical rotation, and comparisons with the reported literature. The spectroscopic analyses of 1 and 2 suggested that 1 is an enantiomer of antifungal N-methylmanzacidin C isolated from the marine sponge Axinella brevistyla, whereas 2 is a diastereomer of manzacidin D at C-11 isolated from the marine sponge Astrosclera willeyana. To the best of our knowledge, this is the first report of the isolation of the pyrrolo-2-aminoimidazole compounds from C. prolifera. Furthermore, in contrast to the potency of N-methylmanzacidin C against Saccharomyces cerevisiae, the antifungal assay revealed that 1 and 2 lack any activity against this strain. Thus, these observations may suggest that the absolute configurations at both C-9 and C-11 play an important role in controlling the antifungal activity of this type of compound. [ABSTRACT FROM AUTHOR]

The cyanobacterial prenyltransferase AmbP3 catalyzes the reverse prenylation of the tetracyclic indole alkaloid hapalindole U at its C-2 position. Interestingly, AmbP3 also accepts hapalindole A, a halogenated C-10 epimer of hapalindole U, and catalyzes normal prenylation at its C-2 position. The comparison of the two ternary crystal structures, AmbP3-DMSPP/hapalindole U and AmbP3-DMSPP/hapalindole A, at 1.65-2.00 Å resolution revealed two distinct orientations for the substrate binding that define reverse or normal prenylation. The tolerance of the enzyme for these altered orientations is attributed to the hydrophobicity of the substrate binding pocket and the plasticity of the amino acids surrounding the allyl group of the prenyl donor. This is the first study to provide the intimate structural basis for the normal and reverse prenylations catalyzed by a single enzyme, and it offers novel insight into the engineered biosynthesis of prenylated natural products. [ABSTRACT FROM AUTHOR]

The Meliaceae family of plants has been shown to contain a vast number of compounds with the potential to be developed for medicinal purposes. We have previously reported the isolation of limonoids from a plant in the Meliaceae family named Chisocheton ceramicus. Ceramicine B was identified as an active compound in inhibiting lipid droplets accumulation (LDA) in the mouse preadipocyte cell line MC3T3-G2/PA6. The presence of ceramicine B was found to inhibit the expression of glucose transporter type 4, lipoprotein lipase, and 11-beta hydroxysteroid dehydrogenase mRNA, and also adipogenic master regulator, peroxisome proliferator-activated receptor-γ, and CCAAT-enhancer-binding protein-α (C/EBPα) mRNA. However, for early adipogenic regulators, such as C/EBPβ and C/EBPδ, and intermediary adipogenic regulators, Krüppel-like factors were unaffected. Western blot analysis showed that ceramicine B was found to inhibit the phosphorylation of Forkhead box O1 (Foxo1), a key process in the insulin signaling pathway. This suggested that the mechanism of anti-LDA activity of ceramicine B was partly via the inhibition of Foxo1 phosphorylation. [ABSTRACT FROM AUTHOR]

Three new terpenoids, opaciniols A–C ( 1– 3), were isolated from the barks of Garcinia opaca, together with malabarica-17,21-dien-3 β,14-diol ( 4) and 13 βH-malabarica-14,17,21-trien-3 β-ol ( 5). Their structures were determined on the basis of NMR spectroscopic data. 3 and 4 showed moderate cytotoxicity against HL-60 cells. [ABSTRACT FROM AUTHOR]

Abstract: In our search for lipid-droplets accumulation (LDA) inhibitors, some ceramicines, a series of limonoids isolated from the barks of Chisocheton ceramicus, were discovered to be active as anti-LDA. Preliminary structure–activity relationships (SAR) of ceramicines as LDA inhibitors based on ceramicines A–L (1–12) and ceramicine B derivatives were described. [Copyright &y& Elsevier]

Abstract Three new lignoids, premnan A (1), premnan B (2), and tauntangyiol C (3), were isolated from Premna serratifolia wood, a traditional cosmetic plant in Myanmar, together with a new lignoid, premnan C (4) assumed to be an artifact, one natural new lignoid (5), and three known lignoids (6 – 8). The structures of the new compounds 1 – 4 were elucidated based on 1D and 2D NMR, IR spectroscopy, and HRESIMS. The absolute configurations of 1 – 4 were also determined by optical rotation, circular dichroism (CD) data analyses, and comparisons with the reported literature. All isolated compounds were tested for their melanogenesis activities against the B16-F10 mouse melanoma cell line. Compounds 1 and 4 showed melanogenesis enhancing activities of 31% and 50%, respectively, at a 50 μM concentration. Compounds 2 , 3 , and 6 increased melanin production by 67%, 30%, and 45%, respectively, at a 100 μM concentration, without any cytotoxicity. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract: A novel C16N-type Lycopodium alkaloid consisting of a decahydroquinoline and a cyclohexanone, huperminone A (1), was isolated from the club moss of Huperzia phlegmaria, and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data. This unique C16N-type skeleton lacking in a nitrogen atom may be generated from C16N2-type phlegmarane skeleton. [Copyright &y& Elsevier]

Two new homodrimane sesquiterpenoids, globbatones A and B (1 and 2), and one 16-norlabdane diterpenoid, globbatone C (3), together with two new naturally occurring, (E)-labda-8(17),12-diene-15,16-olide (4) and γ-bicyclohomofarnesen-12-ol (5), and one known homodrimane sesquiterpenoid (6), nine known labdane diterpenoids (7 – 15), and one isospongian diterpenoid (16), were isolated from the chloroform extract of Globba sherwoodiana rhizomes. The structures of the new compounds 1 – 3 were elucidated based on 1D and 2D NMR and HRESIMS spectroscopic analyses. The chloroform extract of G. sherwoodiana rhizomes and 10 μM concentrations of some of its constituents 1 , 3 , 4 , 8 , 9 , 12 , and 14 showed the moderate anti-Vpr activities, without cytotoxic effects on the TREx-HeLa-Vpr cell line. Unlabelled Image [ABSTRACT FROM AUTHOR]

Two new tetrahydrofuran lignans, taungtangyiols A ( 1 ) and B ( 2 ), and eight known furofuran lignans ( 3 − 10 ), were isolated from the chloroform extract of Premna integrifolia wood collected in Myanmar. Their structures were elucidated by extensive spectroscopic techniques. The X-ray crystal structure of 1 clearly indicated its relative configuration. Taungtangyiols A ( 1 ) and B ( 2 ) inhibited the deposition of melanin in B16F10 mouse melanoma cells, with IC 50 values of 50.7 and 40.9 μM, respectively, without notable cytotoxicity. An SAR study demonstrated that the furofuran and dioxymethylene moieties of the lignans play a vital role in inhibiting melanogenesis. [ABSTRACT FROM AUTHOR]

Abstract: Four new compounds, 2-hydroxy-6-(12′-hydroxyheptadec-13′(E)-en-1-yl)benzoic acid (1), 2-hydroxy-6-(13′-hydroxyheptadec-11′(E)-en-1-yl)benzoic acid (2), 2-hydroxy-6-(10′-hydroxypentadec-11′(E)-en-1-yl)benzoic acid (3), and 2-hydroxy-6-(11′-hydroxypentadec-9′(E)-en-1-yl)benzoic acid (4) were isolated from the leaves of Ginkgo biloba and the structures of new ginkgolic acids were deduced on the basis of spectroscopic methods and chemical means. Compounds 1 and 2, and 3 and 4 examined as an inseparable mixture of hydroxyl and double bond positional isomers, were ultimately defined by total synthesis. Compounds 1–4 showed moderate lipid droplets accumulation inhibitory activity on mouse pre-adipocyte cell line, MC3T3-G2/PA6. [Copyright &y& Elsevier]

SmltD is an ATP-dependent ligase that catalyzes the condensation of UDP-MurNAc- l -Ala and l -Glu to form UDP-MurNAc- l -Ala- l -Glu, in the newly discovered peptidoglycan biosynthesis pathway of a Gram-negative multiple-drug-resistant pathogen, Stenotrophomonas maltophilia. Phytochemical investigation of the 70% ethanol extract from Woodfordia fruticosa flowers collected in Myanmar led to the identification of anti-SmltD active flavonoids, kaempferol 3- O -(6′′-galloyl)- β - d -glucopyranoside (1), astragalin (2), and juglalin (3). Among them, 1 showed the most potent SmltD inhibitory activity. An enzyme steady-state kinetic study revealed that 1 exerted competitive inhibition with respect to ATP. The results of this study provided an attractive foundation for the further development of novel inhibitors of SmltD. [ABSTRACT FROM AUTHOR]