in vitro

Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG).: Phytomedicine. 2007 Aug;14(7-8):551-5 Authors: Kwon OS, Han JH, Yoo HG, Chung JH, Cho KH, Eun HC, Kim KH

Green tea is a popular worldwide beverage, and its potential beneficial effects such as anti-cancer and anti-oxidant properties are believed to be mediated by epigallocatechin-3-gallate (EGCG), a major constituent of polyphenols. Recently, it was reported that EGCG might be useful in the prevention or treatment of androgenetic alopecia by selectively inhibiting 5alpha-reductase activity. However, no report has been issued to date on the effect of EGCG on human hair growth. This study was undertaken to measure the effect of EGCG on hair growth in vitro and to investigate its effect on human dermal papilla cells (DPCs) in vivo and in vitro. EGCG promoted hair growth in hair follicles ex vivo culture and the proliferation of cultured DPCs. The growth stimulation of DPCs by EGCG in vitro may be mediated through the upregulations of phosphorylated Erk and Akt and by an increase in the ratio of Bcl-2/Bax ratio. Similar results were also obtained in in vivo dermal papillae of human scalps. Thus, we suggest that EGCG stimulates human hair growth through these dual proliferative and anti-apoptotic effects on DPCs.

PMID: 17092697 [PubMed - indexed for MEDLINE]

Effect of valerian, valerian/hops extracts, and valerenic acid on glucuronidation in vitro.: Xenobiotica. 2007 Feb;37(2):113-23 Authors: Alkharfy KM, Frye RF

Valerian preparations alone or in combination with hops are popular over-the-counter products used for sleep disturbances or anxiety. Therefore, it is important to characterize the effect of these products on the activity of human drug-metabolizing enzymes. The inhibitory effects of valerian and valerian/hops extracts as well as valerenic acid (a major constituent of valerian) on glucuronidation were evaluated in human liver microsomes and with expressed uridine 5'-diphosphate (UDP)-glucuronosyltransferases (UGT). Methanolic extracts of two herbal preparations caused significant reductions in the rate of formation of acetaminophen, oestradiol, morphine, and testosterone glucuronides. Oestradiol glucuronidation at the 3-hydroxy position was inhibited by nearly 87% in microsomal incubations. In addition, marked reductions in UGT1A1 and UGT2B7 activities were observed in the presence of the herbal extracts using oestradiol and morphine as probe substrates, respectively. Valerenic acid also demonstrated significant inhibitory effects on the glucuronidation of acetaminophen, oestradiol, and morphine with both microsomes and expressed UGTs. The relatively low IC50 values obtained for valerenic acid in microsomal incubations may indicate that this essential oil contributes to the effects observed with herbal extracts in inhibiting glucuronidation in vitro. Overall, these findings suggest that valerian-containing products may interfere with the glucuronidation of endo- and xenobiotics.

In vitro and in vivo anti-retroviral activity of the substance purified from the aqueous extract of Chelidonium majus L.: Antiviral Res. 2006 Nov;72(2):153-6 Authors: Gerencer M, Turecek PL, Kistner O, Mitterer A, Savidis-Dacho H, Barrett NP

We have isolated a substance with anti-retroviral activity from the freshly prepared crude extract of Chelidonium majus L. (greater celandine) by 9-aminoacridine precipitation method and ion exchange chromatography using Dowex-50W/H+ resin followed by the gel filtration on Sephadex-75 column. Elemental and phenol/sulfuric acid method analyses as well as the mass spectrometry of the purified substance indicated that it may represent a low-sulfated poly-glycosaminoglycan moiety with molecular weight of approximately 3800 Da. The substance prevented infection of human CD4+ T-cell lines AA2 and H9 with HIV-1 at concentration of 25 microg/mL as well as the cell-to-cell virus spread in H9 cells continuously infected with HIV-1, as determined by the measurement of reverse transcriptase activity and p24 content in cell cultures. Furthermore, we have shown in a murine AIDS model that the treatment with purified substance significantly prevented splenomegaly and the enlargement of cervical lymph nodes in C57Bl/6 mice chronically infected with the pool of murine leukemia retroviruses. The mechanism(s) of anti-retroviral activity of this substance have to be elucidated.

Analysis of the interaction of phytoestrogens and synthetic chemicals: An in vitro/in vivo comparison.: Toxicol Appl Pharmacol. 2006 Dec 5; Authors: Charles GD, Gennings C, Tornesi B, Kan HL, Zacharewski TR, Bhaskar Gollapudi B, Carney EW

In the evaluation of chemical mixture toxicity, it is desirable to develop an evaluation paradigm which incorporates some critical attributes of real world exposures, particularly low dose levels, larger numbers of chemicals, and chemicals from synthetic and natural sources. This study evaluated the impact of low level exposure to a mixture of six synthetic chemicals (SC) under conditions of co-exposure to various levels of plant-derived phytoestrogen (PE) compounds. Estrogenic activity was evaluated using an in vitro human estrogen receptor (ER) transcriptional activation assay and an in vivo immature rat uterotrophic assay. Initially, dose-response curves were characterized for each of the six SCs (methoxyclor, o,p-DDT, octylphenol, bisphenol A, beta-hexachlorocyclohexane, 2,3-bis(4-hydroxyphenyl)-propionitrile) in each of the assays. The six SCs were then combined at equipotent ratios and tested at 5-6 dose levels spanning from very low, sub-threshold levels, to a dose in which every chemical in the mixture was at its individual estrogenic response threshold. The SC mixtures also were tested in the absence or presence of 5-6 different levels of PEs, for a total of 36 (in vitro) or 25 (in vivo) treatment groups. Both in vitro and in vivo, low concentrations of the SC mixture failed to increase estrogenic responses relative to those induced by PEs alone. However, significant increases in response occurred when each chemical in the SC mixture was near or above its individual response threshold. In vitro, interactions between high-doses of SCs and PEs were greater than additive, whereas mixtures of SCs in the absence of PEs interacted in a less than additive fashion. In vivo, the SC and PE mixture responses were consistent with additivity. These data illustrate a novel approach for incorporating key attributes of real world exposures in chemical mixture toxicity assessments, and suggest that chemical mixture toxicity is likely to be of concern only when the mixture components are near or above their individual response thresholds. However, these data suggest that extrapolation from in vitro assays to in vivo mixture effects should be approached with caution.

In vitro antibacterial activity of some plant essential oils.:
BMC Complement Altern Med. 2006;6:39 Authors: Prabuseenivasan S, Jayakumar M, Ignacimuthu S

BACKGROUND: To evaluate the antibacterial activity of 21 plant essential oils against six bacterial species. METHODS: The selected essential oils were screened against four gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and two gram-positive bacteria Bacillus subtilis and Staphylococcus aureus at four different concentrations (1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The MIC of the active essential oils were tested using two fold agar dilution method at concentrations ranging from 0.2 to 25.6 mg/ml. RESULTS: Out of 21 essential oils tested, 19 oils showed antibacterial activity against one or more strains. Cinnamon, clove, geranium, lemon, lime, orange and rosemary oils exhibited significant inhibitory effect. Cinnamon oil showed promising inhibitory activity even at low concentration, whereas aniseed, eucalyptus and camphor oils were least active against the tested bacteria. In general, B. subtilis was the most susceptible. On the other hand, K. pneumoniae exhibited low degree of sensitivity. CONCLUSION: Majority of the oils showed antibacterial activity against the tested strains. However Cinnamon, clove and lime oils were found to be inhibiting both gram-positive and gram-negative bacteria. Cinnamon oil can be a good source of antibacterial agents.

In vitro determination of the contraceptive spermicidal activity of a composite extract of Achyranthes aspera and Stephania hernandifolia on human semen.: Contraception. 2006 Mar;73(3):284-8 Authors: Paul D, Bera S, Jana D, Maiti R, Ghosh D

OBJECTIVE: To evaluate the effect of a 50% ethanolic extract of the leaf of Stephania hernandifolia and the root of Achyranthes aspera on sperm motility and function in a ratio of 1:3 by weight at different concentrations. RESULTS: Concentration of 0.08 g/mL of the extract affected the motility, and at a concentration of 0.16 g/mL, the sperm motility was reduced to 20% immediately (within 20 s). At a concentration of 0.32 g/mL, this composite extract showed the most promising results by complete sperm immobilization within 2 min after the application of the extract. The effects were spermicidal but not spermiostatic as sperm immobilization effect was found to be irreversible. Sperm viability was decreased significantly and was found to be nonviable after 30 min when treated with the composite extract at a concentration of 0.32 g/mL. The hypo-osmotic swelling of these sperm was reduced significantly at this highest concentration, indicating that the crude extract may probably cause injury to the sperm plasma membrane. A low concentration of 0.04 g/mL is ineffective. CONCLUSION: The findings indicate that this composite plant extract possesses potential contraceptive spermicidal activity in vitro.

Effect of artemisinin/artesunate as inhibitors of hepatitis B virus production in an "in vitro" replicative system.: Antiviral Res. 2005 Nov;68(2):75-83 Authors: Romero MR, Efferth T, Serrano MA, Castaño B, Macias RI, Briz O, Marin JJ

The antiviral effect against hepatitis B virus (HBV) of artemisinin, its derivative artesunate and other compounds highly purified from traditional Chinese medicine remedies, were investigated. HBV production by permanently transfected HepG2 2.2.15 cells was determined by measuring the release of surface protein (HBsAg) and HBV-DNA after drug exposure (0.01-100 microM) for 21 days. The forms of HBV-DNA released were investigated by Southern-blotting. Neutral Red retention test was used to evaluate drug-induced toxicity on host cells. The compounds were classified according to their potential interest as follows: (i) none: they had no effect on viral production (daidzein, daidzin, isonardosinon, nardofuran, nardosinon, tetrahydronardosinon and quercetin); (ii) low: they were able to markedly reduce viral production, but also induced toxicity on host cells (berberine and tannic acid) or they had no toxic effect on host cells but only had a moderate ability to reduce viral production (curcumin, baicalein, baicalin, bufalin, diallyl disulphide, glycyrrhizic acid and puerarin); (iii) high: they induced strong inhibition of viral production at concentrations at which host cell viability was not affected (artemisinin and artesunate). Moreover, artesunate in conjunction with lamivudine had synergic anti-HBV effects, which warrants further evaluation of artemisinin/artesunate as antiviral agents against HBV infection.

Centella asiatica accelerates nerve regeneration upon oral administration and contains multiple active fractions increasing neurite elongation in-vitro.: J Pharm Pharmacol. 2005 Sep;57(9):1221-9 Authors: Soumyanath A, Zhong YP, Gold SA, Yu X, Koop DR, Bourdette D, Gold BG

Axonal regeneration is important for functional recovery following nerve damage. Centella asiatica Urban herb, also known as Hydrocotyle asiatica L., has been used in Ayurvedic medicine for centuries as a nerve tonic. Here, we show that Centella asiatica ethanolic extract (100 microg mL-1) elicits a marked increase in neurite outgrowth in human SH-SY5Y cells in the presence of nerve growth factor (NGF). However, a water extract of Centella was ineffective at 100 microg mL-1. Sub-fractions of Centella ethanolic extract, obtained through silica-gel chromatography, were tested (100 microg mL-1) for neurite elongation in the presence of NGF. Greatest activity was found with a non-polar fraction (GKF4). Relatively polar fractions (GKF10 to GKF13) also showed activity, albeit less than GKF4. Thus, Centella contains more than one active component. Asiatic acid (AA), a triterpenoid compound found in Centella ethanolic extract and GKF4, showed marked activity at 1 microM (microg mL-1). AA was not present in GKF10 to GKF13, further indicating that other active components must be present. Neurite elongation by AA was completely blocked by the extracellular-signal-regulated kinase (ERK) pathway inhibitor PD 098059 (10 microM). Male Sprague-Dawley rats given Centella ethanolic extract in their drinking water (300-330 mg kg-1 daily) demonstrated more rapid functional recovery and increased axonal regeneration (larger calibre axons and greater numbers of myelinated axons) compared with controls, indicating that the axons grew at a faster rate. Taken together, our findings indicate that components in Centella ethanolic extract may be useful for accelerating repair of damaged neurons.

Neutralizing properties of Musa paradisiaca L. (Musaceae) juice on phospholipase A2, myotoxic, hemorrhagic and lethal activities of crotalidae venoms.: J Ethnopharmacol. 2005 Apr 8;98(1-2):21-9 Authors: Borges MH, Alves DL, Raslan DS, Piló-Veloso D, Rodrigues VM, Homsi-Brandeburgo MI, de Lima ME

The use of plants as medicine has been referred to since ancient peoples, perhaps as early as Neanderthal man. Plants are a source of many biologically active products and nowadays they are of great interest to the pharmaceutical industry. The study of how people of different culture use plants in particular ways has led to the discovery of important new medicines. In this work, we verify the possible activity of Musa paradisiaca L. (Musaceae) against the toxicity of snake venoms. Musa paradisiaca, an important source of food in the world, has also been reported to be popularly used as an anti-venom. Interaction of Musa paradisiaca extract (MsE) with snake venom proteins has been examined in this study. Phospholipase A2 (PLA2), myotoxic and hemorrhagic activities, including lethality in mice, induced by crotalidae venoms were significantly inhibited when different amounts of MsE were mixed with these venoms before assays. On the other hand, mice that received MsE and venoms without previous mixture or by separated routes were not protected against venom toxicity. Partial chemical characterization of MsE showed the presence of polyphenols and tannins and they are known to non-specifically inactivate proteins. We suggest that these compounds can be responsible for the in vitro inhibition of the toxic effects of snake venoms. In conclusion, according to our results, using mice as experimental model, MsE does not show protection against the toxic effects of snake venoms in vivo, but if was very effective when the experiments were done in vitro.

[Vitexicarpin, a flavonoid from Vitex trifolia L., induces apoptosis in K562 cells via mitochondria-controlled apoptotic pathway]: Yao Xue Xue Bao. 2005 Jan;40(1):27-31 Authors: Wang HY, Cai B, Cui CB, Zhang DY, Yang BF

AIM: To investigate the inhibitory effect of vitexicarpin on the proliferation of human cancer cells and its mechanism of action. METHODS: The inhibitory effect of vitexicarpin on the proliferation of human cancer cells was evaluated by the SRB method and its apoptosis-inducing effect was demonstrated by morphological observation under light microscope, flow cytometric analysis and agarose gel electrophoresis. The proteins related to apoptosis were examined by Western blotting analysis. RESULTS: Vitexicarpin significantly inhibited the proliferation of human cancer cells, A2780, HCT-15, HT-1080 and K562, with the IC50 values of (19.1 +/- 2.4) micromol x L(-1) for A2780(48 h), (0.66 +/- 0.10) micromol x L(-1) for HCT-15(48 h), (0.44 +/- 0.06) micromol x L(-1) for HT-1080 (48 h) and (0.28 +/- 0.14) micromol x L(-1) for K562 (24 h). The cells treated with vitexicarpin showed characteristic morphology typical for apoptosis and gave dose-dependent sub-G0/G1 peak in the flow cytometric analysis and DNA ladder on agarose gel electrophoresis. In Western blotting analysis, the cleavage of PARP and caspase-3, the release of cytochrome c from mitochondria into the cytosol, the decrease of Bcl-2 expression level, and the down-regulation of the ratio of Bcl-2/Bax expression level were examined in the K562 cells treated with vitexicarpin. CONCLUSION: Vitexicarpin induces apoptosis in K562 cells via mitochondria-controlled apoptotic pathway.