1,9-Caryolanediol 9-acetate

Chemical Transformations of the Fungal Meroterpenoid Dhilirolide A Reveal Skeletal Degradation and Rearrangement Reactions with Biosynthetic Implications.[Pubmed:28805391]

Org Lett. 2017 Sep 1;19(17):4488-4491.

Treatment of the fungal meroterpenoid dhilirolide A (1) with either sodium azide or perchloric acid results in conversion of the dhilirane carbon skeleton of 1 to the 14,15-dinordhilirane carbon skeleton of the products 5-7, with and without concomitant transfer of an acetyl residue to form a C-9 acetate ester. The discovery of these transformations, which are vinylogous retro-Claisen-type condensations, suggests an efficient biogenetic route to 14,15-dinordhiliranes such as dhilirolide K (3).

Two new lignans from the resin of Bursera microphylla A. gray and their cytotoxic activity.[Pubmed:28920481]

Nat Prod Res. 2017 Sep 18:1-6.

Two new lignans, namely 7-O-podophyllotoxinyl butyrate (1) and dihydroclusin 9-acetate (2), were isolated from the dichloromethane fraction of a methanol extract of Bursera microphylla (Burseraceae), along with eight known lignans (3-10). Their structures were determined by means of comprehensive spectroscopic analysis. Lignans 2-6 were tested for their anti-proliferative activity on the cancer cell lines LS180, A549 and HeLa, and on a non-cancer cell line, ARPE-19. Only compounds 4 and 5 showed an interesting activity on HeLa cells.

[Lignans from cultivated Gynura nepalensis].[Pubmed:28884539]

Zhongguo Zhong Yao Za Zhi. 2016 Apr;41(8):1456-1460.

Taking application of some isolation and purification technologies, including solvent extraction, rude solvent isolation, column chromatographies on silica gel and Sephadex LH-20 , and preparative HPLC , 4 compounds were obtained from Gynura nepalensis cultivated in a suburban area of Beijing. Their structures were identified by spectroscopic methods in conjunction with comparison of the NMR data with literature values as 7S,8R-9'-O-ethyl-dehydrodiconiferyl-9-acetate (1), 9'-O-ethyl-dehydrodiconiferyl alcohol (2), dehydrodiconiferyl-9,9'-diacetate(3), and (+)-medioresinol(4), respectively. 1 is a new 2,3-dihydrobenzofuran-8,3'-neolignane type compound, and 2-4 were isolated from G.nepalensis for the first time. The complete assignment of the 1H- and 13C-NMR spectroscopic data of the four compounds recorded in DMSO-d6 was achieved.

Phenolics from Mikania micrantha and Their Antioxidant Activity.[Pubmed:28698451]

Molecules. 2017 Jul 8;22(7). pii: molecules22071140.

A phytochemical study on the aerial parts of Mikania micrantha led to the isolation of two new phenolic compounds, benzyl 5-O-beta-d-glucopyranosyl-2,5-dihydroxybenzoate (1) and (7S,8R)-threo-dihydroxydehydrodiconiferyl alcohol 9-acetate (2), together with twelve known compounds, benzyl 2-O-beta-d-glucopyranosyl-2,6-dihydroxybenzoate (3), 4-allyl-2,6-dimethoxyphenol glucoside (4), (+)-isolariciresinol (5), icariol A(2) (6), 9,10-dihydroxythymol (7), 8,9,10-trihydroxythymol (8), caffeic acid (9), p-coumaric acid (10), ethyl protocatechuate (11), procatechuic aldehyde (12), 4-hydroxybenzoic acid (13), and hydroquinone (14). Their structures were elucidated on the basis of extensive spectroscopic analysis. Except 8 and 9, all the other compounds were isolated from this plant species for the first time. The antioxidant activity of those isolated compounds were evaluated using three different assays. Compounds 1, 2, 3, 9, 10, 13, and 14 demonstrated significant 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) free radical cation scavenging activity ranging from SC50 0.31 to 4.86 microM, which were more potent than l-ascorbic acid (SC50 = 10.48 microM). Compounds 5, 9, 11, and 12 exhibited more potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (SC50 = 16.24-21.67 microM) than l-ascorbic acid (39.48 microM). Moreover, the ferric reducing antioxidant power (FRAP) of compounds 2, 5, 9, and 11 were discovered to be also comparable to or even more potent than l-ascorbic acid.

Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH.[Pubmed:23869882]

J Agric Food Chem. 2013 Aug 14;61(32):7679-88.

Biochar is often considered a strong heavy metal stabilizing agent. However, biochar in some cases had no effects on, or increased the soluble concentrations of, heavy metals in soil. The objective of this study was to determine the factors causing some biochars to stabilize and others to dissolve heavy metals in soil. Seven small arms range soils with known total organic carbon (TOC), cation exchange capacity, pH, and total Pb and Cu contents were first screened for soluble Pb and Cu concentrations. Over 2 weeks successive equilibrations using weak acid (pH 4.5 sulfuric acid) and acetate buffer (0.1 M at pH 4.9), Alaska soil containing disproportionately high (31.6%) TOC had nearly 100% residual (insoluble) Pb and Cu. This soil was then compared with sandy soils from Maryland containing significantly lower (0.5-2.0%) TOC in the presence of 10 wt % (i) plant biochar activated to increase the surface-bound carboxyl and phosphate ligands (PS450A), (ii) manure biochar enriched with soluble P (BL700), and (iii) unactivated plant biochars produced at 350 degrees C (CH350) and 700 degrees C (CH500) and by flash carbonization (corn). In weak acid, the pH was set by soil and biochar, and the biochars increasingly stabilized Pb with repeated extractions. In pH 4.9 acetate buffer, PS450A and BL700 stabilized Pb, and only PS450A stabilized Cu. Surface ligands of PS450A likely complexed and stabilized Pb and Cu even under acidic pH in the presence of competing acetate ligand. Oppositely, unactivated plant biochars (CH350, CH500, and corn) mobilized Pb and Cu in sandy soils; the putative mechanism is the formation of soluble complexes with biochar-borne dissolved organic carbon. In summary, unactivated plant biochars can inadvertently increase dissolved Pb and Cu concentrations of sandy, low TOC soils when used to stabilize other contaminants.