Nguyen Thi Minh Hang

Phthalides and Other Metabolites from Roots of Ligusticum wallichii

A new phthalide that was identified using NMR and mass spectral data as (±)-3-methoxysedanenolide (1) and the nine known compounds sedanenolide (2), Z-ligustilide (3), Z-butylidenephthalide (4), methyl ferulate (5), trans-ferulic (6) and trans-isoferulic acids (7), falcarindiol (8), β-sitosterol (9), and daucosterol (10) were isolated from the MeOH extract of roots of Ligusticum wallichii. Compounds 7 and 8 exhibited high inhibitory activity against NO formation in RAW264.7 cells.

1H and 13C NMR assignments of new ecdysteroids from Callisia fragrans

Ecdysteroids are a class of insect hormones with a characteristic 7en-6-one moiety in the B-ring of polyhydroxysteroids. They were discovered as insect molting hormones. These compounds display important physiological effects on insects and play defensive role. Ecdysteroids also exert beneficial pharmacological properties such as decreasing the blood cholesterol and glucose level in experimental animals, anticancer, and wound healing activities. The increasing numbers of patents have been deposited concerning various beneficial effects of ecdysteroids in many medical or cosmetic domains, whichmake ecdysteroids very attractive candidates for several practical uses. Callisia fragrans (Lindl.) belongs to Commelinaceae family and is native in South America. Chemical studies of this plant showed the presence of phenolic compounds and amino acids. In addition, the methanol extract of C. fragrans showed antiherpetic activity. In this paper, we report the isolation and structure determination of three new and two known ecdysteroids from the stems of C. fragrans.

SYNTHESIS AND APPLICATION OF CHITOSAN/GRAPHENE OXIDE/MAGNETITE NANOSTRUCTURED COMPOSITE FOR Fe(III) REMOVAL FROM AQUEOUS SOLUTION

In this research, the potential of chitosan/Fe 3 O 4 /graphene oxide (CS/Fe 3 O 4 /GO) nanocomposite for efficient removal of Fe(III) a cationic metal ion from aqueous solutions was investigated. The synthesized CS/Fe 3 O 4 /GO was characterized by XRD, VSM and SEM techniques. Also, the various parameters affecting Fe 3+ removal were investigated. Fe(III) adsorption equilibrium data were fitted well to the Langmuir isotherm and the maximum monolayer capacity (q max ), was calculated from the Langmuir as 6.5 mg.g -1 . The results show that, CS/Fe 3 O 4 /GO nanocomposite, can be used as a cheap and efficient adsorbent for removal of heavy metal ions from aqueous solutions.

Metabolites of the Vietnamese Plant Amaranthus viridis

Amaranthus viridis L. (Amaranthaceae) is cultivated in Vietnam and southeast Asian countries as a food crop and is used as a diuretic, analgesic, and laxative. The herb of A. viridis is used in traditional medicine to treat inflammations, eczema, bronchial asthma, and snake bites. Extracts of the aerial part of A. viridis possess antiviral, antidiabetic, and antitumor properties [1–3]. However, the chemical composition of A. viridis is little studied. Several publications on the isolation from it of amasterol [4], spinasterol, squalene, trilinolein, polyprenols, and phytol [1] are all that is known. Previously, the fatty-acid composition of A. viridis seeds was studied [5]. Herein, we communicate the isolation from stems and leaves of the seven compounds triacontanol (1), palmitic acid (2), spinasterol (3), cycloeucalenol (4), cholesterol (5), oleanolic acid (6), and 3,4-seco-olean-12-en-4-ol-3,28-dicarboxylic acid (7). Compounds 1, 2, and 4–7 were observed for the first time in A. viridis. The cytotoxicities of 3, 4, 6, and 7 were determined. The plant A. viridis was collected in May 2016 in Hung-Yen Province, Vietnam. The species were determined by Dr. N. T. Cuong of the Institute of Ecology and Biological Resources, VAST. A voucher specimen was preserved in the herbarium of the Institute of Marine Biology, VAST, Vietnam. Air-dried stems and leaves of A. viridis (4.1 kg) were extracted (3 ) with MeOH, which was removed to give a concentrated extract (226 kg) that was suspended in H2O and extracted successively with hexane and EtOAc. The solvents were removed in vacuo to produce hexane fraction AV1 (40 g), and EtOAc fraction AV2 (30 g). Fraction AV1 was separated over a column of silica gel using a n-hexane–EtOAc gradient (100:1 0:1) to produce nine chromatographic fractions AV1.1–AV1.9. Fraction AV1.4 was rechromatographed over silica gel using n-hexane–EtOAc. Subsequent purification of the obtained fractions over Sephadex LH-20 using MeOH–CH2Cl2 (9:1) isolated 1 (15 mg) and 2 (20 mg). Recrystallization of fraction AV1.5 from Me2CO produced 3. Compounds 4 (8 mg) and 5 (10 mg) from fraction AV1.6 were obtained after separation over a column of silica gel using a n-hexane–Me2CO gradient (100:0 80:20). Compound 6 (20 mg) was isolated from fraction AV1.8 (0.6 g) after purification over Sephadex LH-20 using MeOH–CH2Cl2 (8:2). Fraction AV2 was chromatographed over a column of silica gel using a CH2Cl2–MeOH gradient (99:1 0:1) to produce nine fractions AV2.1–AV2.9. Rechromatography over silica gel of fraction AV2.4 using n-hexane–Me2CO with an increasing Me2CO content gave 7 (7.8 mg). Triacontanol (1). C30H62O, white crystals, mp 82–84 C. Mass spectrum ESI, m/z 439 [M + H] +. 1Í NMR spectrum (500 MHz, CDCl3, , ppm J/Hz): 3.63 (2H, t, J = 6.5, H-1), 1.57–1.55 (2H, br.s, H-2), 1.25 (54H, H-3–H-29), 0.88 (3H, t, J = 6.5, H-30) [6]. Palmitic Acid (2). C16H32O2, white crystals, mp 63–64 C. Mass spectrum ESI m/z 257 [M + H] +. 1Í NMR spectrum (500 MHz, CDCl3, , ppm, J/Hz): 2.34 (2H, t, J = 7.5, H-2), 1.63 (2H, m, H-3), 1.25–1.30 (24H, H-4–H-15), 0.88 (3H, t, J = 6.5, H-16) [7].

Eupolauridine alkaloids of Polyalthia nemoralis

Two eupolauridine alkaloids, eupolauridine ( 1 ) and 8-methoxyeupolauridine ( 2 ), together with a phenanthrene compound, 2,7-dihydroxy-3,6-dimethoxyphenanthrene ( 3 ), were isolated from the ethyl acetate extract of Polyalthia nemoralis barks. Their structures were elucidated on the basis of spectroscopic analysis and comparison with related known compounds. These compounds were evaluated the cytotoxicity on seven human cancer cell lines including KB, MCF7, LU-1, HepG2, LNCap, SW626 and SW480.