Augmentation of antioxidative potential of in vitro propagated Mentha piperita L.

131-137Mentha piperita L., as an aromatic culinary herb and a source of variety of phytochemicals including effective antioxidants, is overexploited by food industry. It demands rapid conservation by means of in vitro propagation of improved clones. Here, we have made an attempt to evaluate and augment the antioxidative potential of M. piperita L. by additing a precursor to the tissue culture derived clones and compared it with the in vivo plants so that tissue culture derived plants can serve as an alternative source of drug. M. piperita L. were analyzed for total phenol, flavonoids, total antioxidant activity, free radical scavenging activity and lipid peroxidase activity. Total phenol content in in vivo plants was lesser than in in vitro. In case of total flavonoid content, it also varies through the season where tissue culture derived plants showed similar and continuous production of total flavonoids content. The percentage inhibition of the in vitro plant extract of precursor fed clone was higher than that of in vivo plant extract. Antioxidant capacity of ascorbic acid was used as a reference standard from which plant extracts with potential antioxidant activity were compared. After addition of precursor, the in vitro mint plant proved more efficient in inhibiting lipid peroxidation after one hour than the in vivo plant, which has high absorbance value indicating lipid peroxide formation

Augmentation of antioxidative potential of in vitro propagated Mentha piperita L

Mentha piperita L., as an aromatic culinary herb and a source of variety of phytochemicals including effective antioxidants, is overexploited by food industry. It demands rapid conservation by means of in vitro propagation of improved clones. Here, we have made an attempt to evaluate and augment the antioxidative potential of M. piperita L. by additing a precursor to the tissue culture derived clones and compared it with the in vivo plants so that tissue culture derived plants can serve as an alternative source of drug. M. piperita L. were analyzed for total phenol, flavonoids, total antioxidant activity, free radical scavenging activity and lipid peroxidase activity. Total phenol content in in vivo plants was lesser than in in vitro. In case of total flavonoid content, it also varies through the season where tissue culture derived plants showed similar and continuous production of total flavonoids content. The percentage inhibition of the in vitro plant extract of precursor fed clone was higher than that of in vivo plant extract. Antioxidant capacity of ascorbic acid was used as a reference standard from which plant extracts with potential antioxidant activity were compared. After addition of precursor, the in vitro mint plant proved more efficient in inhibiting lipid peroxidation after one hour than the in vivo plant, which has high absorbance value indicating lipid peroxide formation

In vitro clonal propagation, organogenesis and somatic embryogenesis in Bacopa monnieri (L.) Wettst

Bacopa monnieri (L.) Wettst is a well-known medicinal herb in the Ayurveda. It is also used as laxative and curative for ulcers, inflammation, anaemia, scabies, leucoderma, asthma and epilepsy, enlargement of spleen, leprosy and others. In vitro propagation and regeneration through somatic embryogenesis of B. monnieri has played an important role in the production of healthy, disease-free plants with desirable traits. In B. monnieri, there are few reports which indicate rapid regeneration and somatic embryogenesis. For in vitro clonal propagation, the highest shoot formation was obtained when BAP 2 mg/ l used. The best response for rooting was obtained in IAA 1.0 mg/ l. The recorded survival rate of the plants was 70%. Plants were without any detectable phenotypic variations. Cytological study indicated that the chromosome number remain same (2n= 64) in in vitro and in vivo roots. A rapid, simple and efficient protocol for plantlet regeneration was achieved through embryogenic callus from leaf explants of B. monnieri. Callus induction and embryogenesis were significantly affected by presence/absence and type and concentration of growth regulators. Best organogenic callus induction was obtained in MS medium supplemented with BAP 5mg/ l. For induction of somatic embryogenesis, auxin (2, 4-D 1 mg/ l) was used in the culture medium subsequently in basal media for embryo maturation. Kn 0.2 mg/ l was the best for production of plantlet from embryo. Thus, this can be an easiest protocol for stable clonal propagation and plant regeneration through somatic embryogenesis in B. monnieri. The protocol used here for propagation and regeneration is much easier, low cost and reliable

Efflux Pumps In Antimicrobial Resistance: Mechanism, Regulation And Therapeutic Implications

Efflux pumps play a crucial role in antimicrobial resistance, enabling bacteria to extrude a wide range of antibiotics and other antimicrobial compounds, thereby reducing their intracellular concentration and rendering them ineffective. Understanding the mechanisms underlying efflux pump-mediated resistance is essential for the development of effective strategies to combat this growing threat. This review paper provides an overview of the various efflux pump systems, their regulation mechanisms, and their impact on antimicrobial resistance. Additionally, we discuss the potential therapeutic interventions that target efflux pumps to restore the efficacy of antimicrobial agents

Human placental lipid induces melanogenesis by increasing the expression of tyrosinase and its related proteins in vitro

Lipids, particularly sphingolipids, are emerging as novel regulators of cellular activity. A placental total lipid fraction (PTLF), the total lipid prepared from an hydroalcoholic extract of fresh term human placenta, was previously shown to have a pigmentinducing activity in an animal model. The PTLF contains sphingolipids which stimulate DNA synthesis and melanin formation with marked morphological changes in B16F10 melanoma cells. In order to identify the mechanism underlying the increased melanin synthesis, B16F10 cells were treated with PTLF to assess the catalytic activities of tyrosinase (i.e. tyrosine hydroxylase and DOPA oxidase), the key regulatory enzyme of melanin synthesis. Tyrosine hydroxylase (estimated by the release of 3H2O) as well as DOPA oxidase (measured spectrophotometrically and also in non-denaturing gels), was stimulated significantly by PTLF. Western blot analysis demonstrated an increase in the expression of tyrosinase, tyrosinase related proteins 1 and 2 (TRP1 and TRP2) at the protein level and RT-PCR analysis revealed stimulated transcription of tyrosinase, TRP1 and TRP2 mRNAs in PTLF-treated B16F10 cells. Actinomycin D and cycloheximide, inhibitors of transcription and translation, respectively, inhibited PTLF-induction of tyrosinase activity with a corresponding decrease in melanogenesis. In all cases, the response to PTLF was similar to that induced by a-melanocyte stimulating hormone, a well-known stimulator of melanogenesis. Thus, these results provide the basis of action of PTLF stimulated melanogenesis in B16F10 cells showing that this placental extract is a strong inducer of pigmentation at the transcriptional and translational levels

Human placental lipid induces melanogenesis through p38 MAPK in B16F10 mouse melanoma

Melanogenesis is one of the characteristic functional activities of melanocyte/melanoma and is regulated via mitogen-activated protein kinase (MAPK) and Akt/protein kinase B (PKB) pathways. Placental total lipid fraction (PTLF), prepared from a hydroalcoholic extract of fresh term human placenta contains sphingolipids and was recently shown to stimulate melanogenesis via up-regulation of the key enzyme tyrosinase in B16F10 mouse melanoma cells. How such lipids mediate their effects on pigmentation and tyrosinase expression is a particularly important aspect of melanogenesis. To study the signaling that leads to tyrosinase expression, we have investigated the roles of the MAPK and Akt/PKB pathways in B16F10 melanoma cells in melanogenesis in response to PTLF. Treatment of cells with PTLF led to the time dependent phosphorylation of p38 MAPK. SB203580, a p38 MAPK inhibitor, completely blocked the PTLF-induced melanogenesis by inhibiting promoter activity and subsequent expression of tyrosinase. Phosphatidylinositol 3- kinase (PI3K) inhibitor, LY294002 a blocker of the Akt signaling pathway, or an inhibitor of MEK (MAPK/ERK Kinase), PD98059 when included along with PTLF was found to potentiate PTLF-induced phosphorylation of p38 MAPK together with tyrosinase expression and melanogenesis. The results suggest that the activation of p38 MAPK plays a crucial role in PTLF-induced B16F10 melanogenesis by up-regulating tyrosinase expression

Transcriptional activation of tyrosinase gene by human placental sphingolipid

The sphingolipids, a class of complex bioactive lipids, are involved in diverse cellular functions such as proliferation, differentiation, and apoptosis as well as growth inhibition. Recently sphingosylphosphorylcholine (SPC), sphingosine-1-phosphate (S1P), and C2-ceramide (C2-Cer), sphingolipid containing acetic acid are emerging as melanogenic regulators. A bioactive sphingolipid (PSL) was isolated from hydroalcoholic extract of fresh term human placenta and it induced melanogenesis in an in vitro culture of mouse melanoma B16F10 cells. Tyrosinase, the rate-limiting enzyme for melanogenesis, is required to be upregulated for the increased melanin production. The expression of tyrosinase, both at protein as well as mRNA level, was higher in the PSL treated B16F10 cells as evidenced by Western blot and RT-PCR analysis. Actinomycin D and cycloheximide, inhibitors of transcription and translation, respectively, inhibited PSL-induced tyrosinase activity and its protein expression showing decrease in melanogenesis, correspondingly. The activity of GFP coupled tyrosinase promoter was upregulated in transfected B16F10 cells after treating with PSL as determined by fluorescence microscopy, fluorometric analysis, and Western blot. These results, thus, suggested that PSL upregulated tyrosinase gene expression at transcription level through promoter activation to show increased melanogenesis. Therefore, PSL as an inducer of melanogenesis might account for the recovery of pigment in depigmentation disorder