• Natural Product Sciences
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• v.11 no.3
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• pp.174-178
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• 2005

Oxidative stress is an important causative factor in several human chronic diseases, such as atherosclerosis, cardiovascular disorders, mutagenesis, cancer, several neurodegenerative disorders, and the aging process. Phenolics and tannins are reported to be good antioxidants. Anogeissus latifolia (Combretaceae) bark has been used in the Indian traditional systems of medicine for curing a variety of ailments, but scientific validation is not available till date. Hence the present study was undertaken to isolate antioxidant compounds by activity-guided isolation. Inhibtion of diphenyl picryl hydrazyl (DPPH) and Xanthine oxidase along with photochemiluminescence assay were used as bioassay for antioxidant activity. Activity guided isolation was carried out using silica column and the compounds were quantified using HPLC. Ethyl acetate and butanol fraction exhibited potent antioxidant activity. Bioassay-guided isolation led to isolation of ellagic acid (1) and dimethyl ellagic acid (2) as the main active compounds, which along with gallic acid were quantified by HPLC. Thus we conclude that these three major tannoid principles present in A. latifolia, are responsible for the antioxidant potential and possibly their therapeutic potential.

• Archives of Pharmacal Research
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• v.21 no.1
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• pp.67-69
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• 1998

Three TNF-$\alpha$inhibitory lignans were isolated from the flower buds of Magnolia fargesii through bioassay-guided isolation. They were identified as eudesmin, magnolin and lirioresinol-B dimethylether on the basis of their spectroscopic data. All three lignans showed inhibitory effects on TNF-$\alpha$ production in LPS-stimulated murine macrophage cell line, RAW264.7 and eudesmin showed the strongest activity ($IC_{50}=51{\mu}M)$.

• Archives of Pharmacal Research
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• v.26 no.2
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• pp.147-150
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• 2003

To find anticancer agents from higher plants, DNA strand-scission assay method was employed for bioassay-guided fractionation as well as for screening the crude extracts. During the screening, an ethyl acetate extracts of the heartwood of Caesalpinia sappan L. (Leguminosae) exhibited potent DNA strand-scission activity. Therefore, the ethyl acetate extracts of the dried heartwood of C. sappan was subjected to the bioassay-guided fractionation, which led to the isolation of a known compound, brazilin (1) as the active constituent. In addition, caesalpine J (2) was also isolated as an inactive constituent.

• Natural Product Sciences
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• v.4 no.3
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• pp.180-183
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• 1998

The ethanol extract from the leaves of Juniperus chinensis was found to be cytotoxic towards HeLa cells. Bioassay-guided fractionation of the EtOAc soluble faction directed by the microtitration cytotoxic assay revealed that the cytotoxic compound was deoxypodophyllotoxin. All the tumour cell lines tested (KU8112F-chronic mylogeneous leukemia, TK 10-renal carcinoma, UACC 62-melanoma and CEM-SS-T-lymphoblastic leukemia) were found to be susceptible to deoxypodophyllotoxin, however, the minimum effective concentration (MEC) required to reduce the cell population by 100 percent was different between cell lines.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.559-561
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• 1996

A minor cytotoxic compound was isolated by bioassay-guided fractionation from Asiasari Radix and identified as aristolactam III(1) on the basis of spectral data and chemical evidence. This is the first report on the isolation of compound 1 from Asiasarum genus. Compound 1 exhibited a significant cytotoxic activity against the three kinds of human cancer cell lines (A 549, SK-MEL-2 and SK-OV-3).

• Archives of Pharmacal Research
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• v.26 no.9
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• pp.735-738
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• 2003

The methanolic extract of the twigs of Celtis chinensis was found to show inhibitory activity on acetylcholinesterase (AChE), an enzyme that plays a role in the metabolic hydrolysis of ACh. Bioassay-guided fractionation of the methanolic extract resulted in the isolation of N-p-coumaroyl tyramine. as an inhibitor on AChE. This compound inhibited AChE activity in a dose-dependent manner, and the $IC_50$ value of trans-N-p-coumaroyl tyramine was 34.5 $\mu$g/mL (122 $\mu$M).

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.615-618
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• 2016

Ethyl acetate extracts obtained from culture of endophytic fungi Aspergillus sp isolated from Piper crocatum Ruiz & Pav, have been shown to possess cytotoxic activity against T47D breast cancer cells. Investigations were here conducted to determine bioactive compounds responsible for the activity. Bioassay guided fractionation was employed to obtain active compounds. Structure elucidation was performed based on analysis of LC-MS, $^1H$-NMR, $^{13}C$-NMR, COSY, DEPT, HMQC, HMBC data. Cytotoxity assays were conducted in 96 well plates against T47D and Vero cell lines. Bioassay guided isolation and chemical investigation led to the isolation of pyrophen, a 4-methoxy-6-(1'-acetamido-2'-phenylethyl)-2H-pyran-2-one. Further analysis of its activity against T47D and Vero cells showed an ability to inhibit the growth of T47D cells with IC50 values of $9.2{\mu}g/mL$ but less cytotoxicity to Vero cells with an $IC_{50}$ of $109{\mu}g/mL$. This compound at a concentration of 400 ng/mL induced S-phase arrest in T47D cells.

• Natural Product Sciences
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• v.22 no.3
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• pp.193-200
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• 2016

This study describes the anti-inflammatory, anti-oxidant, and melanogenesis inhibition activities of methanol extract and various organic solvent fractions of Arecae Pericarpium. We examined the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells, 1,1-diphenyl-2-picrylhydrazine (DPPH) scavenging activity, mushroom tyrosinase inhibition activity and melanin contents. The study showed that, among all tested fractions, methylene chloride fraction showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells ($IC_{50}$ value $8.89{\mu}g/mL$) and DPPH radical scavenging activity ($EC_{50}$ value $21.39{\mu}g/mL$). Methylene chloride and ethyl acetate fractions similarly inhibited mushroom tyrosinase activity. Methanol extract exhibited strongest reduction of melanin content in B16F10 melanoma cells. Based on the bioactivity assay results, methylene chloride and ethyl acetate fractions were further separated. Eight phenolic compounds were isolated, which are dimeric syringol (1), catechol (2), 4-hydroxybenzaldehyde (3), vanillin (4), 4-hydroxyacetophenone (5), apocynin (6), protocatechuic acid (7) and 4-hydroxybenzoic acid (8). Among the isolated compounds tested, catechol showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells. Catechol also showed the concentration-dependent NF-${\kappa}B$ inhibition activity. Arecae Pericarpium might have potentials to be developed as anti-inflammatory agent or dermatological product for skin-whitening agent.

• Archives of Pharmacal Research
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• v.28 no.8
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• pp.892-896
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• 2005

In order to isolate substances that inhibit the hemolytic activity of human serum against eryth-rocytes, we have evaluated whole plants of the Orostachys japonicus species with regard to its anti-complement activity, and have identified its active principles following activity-guided isolation. A methanol extract of the O. japonicus, as well as its n-hexane soluble fraction, exhibited significant anti-complement activity on the complement system, which was expressed as total hemolytic activity. A bioassay-guided chromatographic separation of the constituents resulted in the isolation of three known compounds 1-3 from the active n-hexane fraction. The structure of these compounds were analyzed, and they were identified as hydroxyhopanone (1), $\beta-sitosteryl-3-O-\beta-D-glucopyranosyl-6'-O-palmitate$ (2), and $\beta-sitosteryl-3-O-\beta-D-glucopyranoside$ (3), respectively. Of these compounds, compound 2 exhibited potent anti-complement activity $(IC_{50}=1.0\pm0.1{\mu}M)$ on the classical pathway of the complement, as compared to tiliroside $(IC_{50}=76.5\pm1.1{\mu}M)$, which was used as a positive control. However, compounds 1 and 3 exhibited no activity in this system.

• Korean Journal of Pharmacognosy
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• v.48 no.2
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• pp.113-118
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• 2017

Bioassay guided fractionation and isolation of the $CH_2Cl_2$ extract from the apical bud of Gardenia sootepensis (Rubiaceae) led to the isolation of five known flavonoids (1-5). The structures of the compounds were determined by 1D and 2D NMR, and MS experiments, as well as by comparison of their data with published values. Compounds 1-5 were isolated for the first time from this plant source. The isolated compounds were evaluated for their cancer chemopreventive potential based on their ability to inhibit nitric oxide (NO) production. Among the isolates, compound 4 exhibited considerable NO inhibitory activity with an $IC_{50}$ value of $13.8{\mu}M$.