Nitric Oxide Inhibitory Effect Research Articles

Iridoids from the aerial parts of Adenosma caeruleum with their nitric oxide inhibitory effects

Three new iridoids, adenocaeroids A−C (1−3), and seven known analogs, umbellatolide B (4), pedicularis-lactone (5), iridolactone (6), artselaenin C (7), eucommiol (8), rehmaglutin D (9), and 3-deoxy-artselaenin C (10) were isolated from the aerial parts of Adenosma caeruleum. Their chemical structures were identified by the comprehensive spectroscopic methods, including 1D and 2D NMR and HRESI mass spectra. The relative configurations of 1−3 were established by analyzing their NOESY spectra as well as by DFT-GIAO NMR calculations followed by ML-J-DP4, DP4+, and DU8 methods. The absolute configurations of 1−3 were determined by comparing experimental and calculated ECD spectra and specific optical rotation values. All of the compounds, except 7 and 10, inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated BV2 microglial cells in a dose-dependent manner, with IC50 values ranging from 28.4−61.8 µM. However, none of the compounds showed inhibitory effect on protein-tyrosine phosphatase 1B (PTP1B) activity.

UPLC-Q-Orbitrap-MS/MS-Guided Isolation of Bioactive Withanolides from the Fruits of Physalis angulata.

Physalis angulata Linn. is an exotic Amazonian fruit that is commonly recognized as wild tomato, winter cherry, and gooseberry. While its fruit is known to contain many nutrients, such as minerals, fibers, and vitamins, few papers have investigated withanolide derivatives from its fruits. UPLC-Q-Orbitrap-MS/MS, which produces fragmentation spectra, was applied for the first time to guide the isolation of bioactive withanolide derivatives from P. angulata fruits. As a result, twenty-six withanolide derivatives, including two novel 1,10-secowithanolides (1 and 2) and a new derivative (3), were obtained. Compounds 1 and 2 are rare rearranged 1,10-secowithanolides with a tetracyclic 7/6/6/5 ring system. All structures were assigned through various spectroscopic data and quantum chemical calculations. Nine withanolide derivatives exhibited significant inhibitory effects on three tumor cell lines with IC50 values of 0.51-13.79 μM. Moreover, three new compounds (1-3) exhibited potential nitric oxide inhibitory effects in lipopolysaccharide-stimulated RAW264.7 cells (IC50: 7.51-61.8 μM). This investigation indicated that fruits of P. angulata could be applied to treat and prevent cancer and inflammatory-related diseases due to their potent active withanolide derivatives.

Eight Indole Alkaloids from the Roots of Maerua siamensis and Their Nitric Oxide Inhibitory Effects.

Maerua siamensis (Capparaceae) roots are used for treating pain and inflammation in traditional Thai medicine. Eight new indole alkaloids, named maeruanitriles A and B, maeroximes A-C, and maeruabisindoles A-C, were isolated from them. Spectroscopic methods and computational analysis were applied to determine the structure of the isolated compounds. Maeroximes A-C possesses an unusual O-methyloxime moiety. The bisindole alkaloid maeruabisindoles A and B possess a rare azete ring, whereas maeruabisindole C is the first indolo[3,2-b]carbazole derivative found in this plant family. Five compounds [maeruanitriles A and B, maeroxime C, maeruabisindoles B, and C] displayed anti-inflammatory activity by inhibiting nitric oxide (NO) production in the lipopolysaccharide-induced RAW 264.7 cells. Maeruabisindole B was the most active inhibitor of NO production, with an IC50 of 31.1 ± 1.8 μM compared to indomethacin (IC50 = 150.0 ± 16.0 μM) as the positive control.

Litsea cubeba fruit attenuates diabetes-associated metabolic complications in mice

BackgroundLitsea cubeba (Lour) Pers. (Lauraceae) fruit has traditionally been used in treatment of diabetes in Sikkim, India. The purpose of the present study is to investigate the antidiabetic activity of methanol extract of Litsea cubeba fruit (MELCF) against streptozotocin (STZ)-induced diabetes in male albino mice. MELCF was assessed for in vitro α amylase, α glucosidase inhibitory activity and in vitro antioxidant activity against 2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide radicals. STZ was given intraperitoneally at 60 mg/kg for consecutive 3 days to mice. MELCF was administered orally in three doses 100 mg/kg, 200 mg/kg, 300 mg/kg body weight to STZ-induced mice. Metformin (200 mg/kg body weight) served as reference. Blood glucose and body weight were checked in seven days interval. After 28 days of treatment, the glycosylated hemoglobin (HbA1c), cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, urea were measured. Hepatic and renal antioxidant parameters of viz. lipid peroxidation (LPO), reduced glutathione (GSH) and superoxide dismutase (SOD) were estimated. The histopathological evaluation of pancreas, liver and kidney was performed.ResultsMELCF demonstrated significant alpha-amylase, DPPH and nitric oxide inhibitory effects. It significantly reduced blood glucose in a dose dependent manner. It has normalizing effect on HbA1c, AST, ALT, TC, TG, urea and creatinine. It has a modulator effect on tissue antioxidant status i.e., LPO, GSH and SOD. Histopathological findings reveled regenerative effect in pancreatic islets, liver and kidney.ConclusionIt can hence be concluded that, Litsea cubeba fruit has significant attenuative effect against diabetic complications in mice.

Structural characterization of phenolic constituents from the rhizome of Imperata cylindrica var. major and their anti-inflammatory activity

As one of raw materials, the rhizome of Imperata cylindrica var. major (Nees) C.E. Hubb. is used in kinds of preparations curing inflammation related diseases, while its effective substances are not yet clear. In this paper, its chemical constituents and their anti-inflammatory activities were investigated. As results, ten compounds, named as imperphenoside A (1), imperphenols B (2) and C (3), imperphenosides D–F (4–6), and imperlignanosides A–D (7–10), along with previously reported thirty-seven known ones (11–47) were obtained from it. Their structures were ascertained basing on the extensive spectroscopic methods and electronic circular dichroism data analysis. Meanwhile, compounds 4, 11, 12, 24, 27, 31, 32, 37, 43, 45, and 47 exhibited nitric oxide inhibitory effects in concentration dependent at 3, 10, and 30 μM on lipopolysaccharides induced RAW 264.7 cells. Moreover, the western blot analysis indicated that compounds 4, 11, 43, and 47 could restrain the phosphorylation of nuclear factor kappa-B kinase to down-regulate the protein expression of inflammatory cytokines such as inducible nitric oxide synthase, interleukin-6 and tumor necrosis factor-α. In conclusion, they might play the anti-inflammatory effects through regulating NF-κB signaling pathway.

Quality and functional characteristics of tofu prepared rapidly from soybeans dried after soaking in water

In this study, Soybeans dried after soaking (SDSs) were prepared for rapid tofu production, and quality and functional characteristics of SDS-tofu were analyzed. SDS40, SDS50, and SDS60 were prepared by soaking for 12 hr and then drying at 40, 50, and 60℃, respectively. During the soaking process in tofu production, the water absorption rate of SDSs was higher than that of control soybeans. SDS-tofu was prepared by soaking SDSs for 1 hr. Quality, texture, and sensory characteristics were similar among tofu samples. SDS-tofu had a higher aglycone isoflavone content (AIC) than did control tofu. SDS60-tofu had the highest AIC, indicating high nitric oxide inhibitory effect. Antioxidant components, activities and cell viabilities were similar among control tofu and SDS-tofu. Consequently, this study presents the possibility of enhancing efficiency of tofu production process and functionality of tofu by using SDSs because of reduction of the soaking time and the improvement of aglycone isoflavone content. Novelty impact statement Soybeans dried after soaking (SDSs) contained much higher contents of aglycone isoflavones than did general-use soybeans because the former was prepared by drying soybeans at 40–60℃ after they had been completely soaked for a long time, thus allowing endogenous β-glucosidase (optimal temperature, 60℃) to be activated, and in particular, glycitein, which was not detected in general-use soybeans, was detected in the SDSs. The use of SDSs can shorten the moisture reabsorption time because the cross-sectional area for moisture absorption is larger in SDSs than in general-use soybeans, likely as the result of porous structures that form in the soybean as it dries after swelling from being soaked. By manufacturing tofu using SDSs, tofu with enhanced characteristics, can be produced quickly due to improvement of the manufacturing process, namely, the time needed for soaking is shorter, and the resulting tofu has a higher content of aglycone isoflavones from the conversion of isoflavones to aglycone isoflavones.

Bioactive secondary metabolites from a soybean-derived fungus Aspergillus versicolor IMBC-NMTP02

• Isolation of 10 compounds from Aspergillus versicolor IMBC-NMTP02. • Structural identification of 3 new, 2 new natural, and 5 known compounds. • Cytotoxicity toward HepG2, KB, HL-60, MCF-7, SK-Mel-2, and LNCaP cancer cells. • Nitric oxide inhibitory effects of the isolated compounds. • Antimicrobial effects of the isolated compounds. In the present study, 10 secondary metabolites, including three new asperversilactones A–C ( 2 , 4 , and 5 ) and two new natural metabolites (4 Z ,6 S ,7 R )-6,7-dihydroxyocta-2,4-dien-4-lactone ( 1 ) and (4 E ,6 S ,7 R )-6,7-dihydroxyocta-2,4-dien-4-lactone ( 3 ) were isolated from a culture fermentation of the soybean-derived fungus Aspergillus versicolor IMBC-NMTP02. Their structures were elucidated by comprehensive analyses of spectroscopic methods, including NMR, mass, and ECD spectra. Compounds 5 , 6 , and 9 were shown to have cytotoxic effects toward the HepG2, KB, HL-60, MCF-7, SK-Mel-2, and LNCaP human cancer cell lines (IC 50 = 31.7–81.5 μM), whereas all of the compounds inhibited NO overproduction in LPS-stimulated BV2 cells (IC 50 = 19.0–41.9 μM). Furthermore, all of the compounds showed antimicrobial effects against Enterococcus faecalis and Candida albican s, with MIC values in the range of 32–256 μM. Our investigation contributes to clarification of the chemical constituents of the soybean-derived A. versicolor and warrants further studies of some bioactive metabolites for therapeutic uses.

Guaianolides from Artemisia codonocephala suppress interleukine-1β secretion in macrophages

Sesquiterpene lactones supply a variety of scaffolds for the development of anti-inflammatory drugs. In this study, eight undescribed guaianolides, i.e., lavandolides A‒H, were isolated from the whole plants of Artemisia codonocephala, together with five known analogues. Their planar structures and relative configurations were elucidated by spectroscopic measurements, and their absolute configurations were determined by electronic circulardichroism spectra and single crystal X-ray diffraction experiments. The nitric oxide inhibitory effect of all the isolates was assessed on lipopolysaccharide stimulated THP-1 macrophages. Lavandolide D showed a potent inhibitory effect on NO production, with IC50 values of 3.31 ± 0.74 μM. Furthermore, lavandolide D inhibited NOD-, LRR- and pyrin domain-containing protein 3 inflammasome-mediated interleukin-1β production through activating autophagy.

Lepipyrrolins A-B, two new dimeric pyrrole 2-carbaldehyde alkaloids from the tubers of Lepidium meyenii

Nine new pyrrole alkaloids, including two undescribed dimeric pyrrole 2‑carbaldehyde alkaloids, lepipyrrolins A-B (1–2), seven pyrrole-alkaloid derivatives, macapyrrolins D–J (3–9), along with three known ones (10–12) were isolated from the rhizomes of Lepidium meyenii. Their structures and absolute configurations were demonstrated by extensive spectroscopic data (1D, 2D NMR, HRESIMS), and calculated electronic circular dichroism (ECD) experiment. Compounds 1, 3–12 were tested for their nitric oxide inhibitory effects. Furthermore, compound 1 was evaluated for its cytotoxic activity against five human tumor cell lines (HL-60, SMMC-7221, A549, MCF-7, and SW480) in vitro, and displayed selective cytotoxicity against SMMC-7721 with IC50 value of 16.78 ± 0.49 μM.

Anti-inflammatory, anti-nociceptive and anti-oxidant activities of carvacrol containing leaf extracts of edible Indian borage plant Plectranthus amboinicus: an in vivo and in vitro approach

Inflammation remains a complex process in host defense system and the pathology caused by it remains unsolved till date. Several steroidal and non-steroidal anti-inflammatory drugs in current use to treat inflammatory diseases elicit side effects in longer run. Hence, in order to counteract these outcomes, a pharmacognistic study using a Lamiaceae plant, Plectranthus amboinicus has been focused in the present study. P. amboinicus commonly known as Indian borage has been used in folk medicine for years in treating numerous diseases. It is well known for the presence of major phytochemical constituents which possess anti-inflammatory properties. Assessment of biochemical constituents and molecular mechanisms behind the anti-inflammatory property of P. amboinicus leaves were carried out in in vivo and in vitro conditions. In vivo studies of formalin-induced nociception and paw edema in mice and for in vitro condition lipopolysaccharide-induced inflammation using IC-21 macrophage cells were performed. Aqueous and ethyl acetate leaf extracts of P. amboinicus were analyzed for its phytochemical constituents. Variations in phytochemical components were noticed in GC-MS analysis. The carvacrol containing ethyl acetate extract exhibited higher anti-nociception in terms of lower paw licking time in the later phase of nociception and lowered hind paw edema volume up to 35%. The biochemical analysis revealed that the oxidative stress markers such as malondialdehyde and antioxidant enzymes have been modulated upon pretreatment with both extracts and also modulated the expression of inducible nitric oxide synthase, cyclooxygenase 2, Interleukin-1β, histamine 1 receptor genes and nuclear factor kappa B protein. In addition, nitric oxide inhibitory effect was observed in P. amboinicus treated IC-21 macrophages. Therefore, the molecular mechanism put forth in this study provides insights that the presence of carvacrol in ethyl acetate extract enhances anti-inflammatory activity.

Antioxidant Potential of Glycyrrhiza Glabra L. Roots: In-Vitro Evidences

Background: The study was aimed to determine the mechanism of antioxidant effects of Glycyrrhiza glabra L. (GG) roots using in-vitro assays. Methods: The various extracts of GG roots were prepared and evaluated for DPPH scavenging, reducing effects and nitric oxide inhibiting activities. Prepared extracts were screened for the presence of various phytochemicals and quantified on the basis of phytochemical present therein. Results: The results showed that all the prepared extracts contained phenolic compounds. Also, extract showed appreciable antioxidant effects in all three assays employed. However, among prepared extracts, ethylacetate extract was found to have strong free radical inhibition, ferric reducing potential and nitric oxide inhibitory effects. The reason for high antioxidant activity in ethylacetate extract could be attributed to the significant amount of phenol compounds present in it. Conclusion: Evidently, GG’s capacity to scavenge free radicals, reducing potential and inhibit nitric oxide contributes to its antioxidant effects and thus, could be a strong candidate for developing antioxidant based drug therapy.

Antioxidant Potential of Glycyrrhiza glabra L. roots: In-Vitro Evidences

Background: The study was aimed to determine the mechanism of antioxidant effects of Glycyrrhiza glabra L. (GG) roots using in-vitro assays.Methods: The various extracts of GG roots were prepared and evaluated for DPPH scavenging, reducing effects and nitric oxide inhibiting activities. Prepared extracts were screened for the presence of various phytochemicals and quantified on the basis of phytochemical present therein.Results: The results showed that all the prepared extracts contained phenolic compounds. Also, extract showed appreciable antioxidant effects in all three assays employed. However, among prepared extracts, ethylacetate extract was found to have strong free radical inhibition, ferric reducing potential and nitric oxide inhibitory effects. The reason for high antioxidant activity in ethylacetate extract could be attributed to the significant amount phenol compounds present in it. Conclusion: Evidently, GG’s capacity to scavenge free radicals, reducing potential and inhibit nitric oxide contributes to its antioxidant effects and thus, could be a strong candidate for developing antioxidant based drug therapy.

Analysis of chemical constituents and six compounds in Qu-feng-sheng-shi Granules via HPLC-ESI-Q/TOF-MSn and HPLC-UV technique.

Qu-feng-sheng-shi Granules (QFSSG), a common prescription for the treatment of chronic inflammation and allergic rhinitis, is widely used in the clinic as a traditional Chinese medicine. Chemical analysis and quality control studies of this formulation are relatively limited compared with pharmacological studies. In this study, a high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (HPLC-ESI-Q/TOF-MSn ) was used to identify the components in this prescription. Next, to quantify six major compounds, an HPLC-UV method was developed and validated. The results showed that 53 compounds were identified based on the MSn data, retention time and previous reports, including 17 coumarins, 14 lignans, 10 chromones, nine phenylethanoid glycosides and three other compounds, were identified or tentatively assigned. Contents of six major bioactive compounds (4'-O-β-glucopyranosyl-5-O-methylvisamminol, Prim-O-glucosylcimifugin, forsythin, magnolin, imperatorin, isoimperatorin) could be determined by HPLC simultaneously. In addition, the potential anti-inflammatory activity of six major compounds was determined too, and we found that four compounds (4'-O-β-glucopyranosyl-5-O-methylvisamminol, Prim-O-glucosylcimifugin, forsythin, imperatorin) have a potent nitric oxide inhibitory effect. In conclusion, this work provided comprehensive information on the quality control of QFSSG and evaluated the potential biological activity of the main components in QFSSG, which can contribute to understanding and using it more scientifically.

Four undescribed sulfur-containing indole alkaloids with nitric oxide inhibitory activities from Isatis tinctoria L. roots

Four undescribed sulfur-containing indole alkaloids, isatisindigoticanines H, I and isatindigosides F, G along with three known analogues were obtained from Isatis tinctoria L. roots. Isatisindigoticanines H and I contained an unusual 1-(thiazol-4-yl)butane-1,2,3,4-tetraol moiety while isatindigosides F and G possessed a new 3-[3-(1H-indole-2-yl)azet-2-yl]-1H-indole skeleton. The putative biosynthetic pathways of isatisindigoticanines H, I and isatindigosides F, G are proposed. The isolated compounds showed nitric oxide inhibitory effects with IC50 values ranging from 4.3 to 70.3 μM.

Withanolides from Physalis peruviana showing nitric oxide inhibitory effects and affinities with iNOS

A phytochemical study to obtain new nitric oxide (NO) inhibitors resulted in the isolation of five new withanolides from the whole plants of Physalis peruviana. The structures were determined on the basis of extensive NMR spectroscopic data analysis as well as the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. The NO inhibitory effects were examined by inhibiting NO release in lipopolysaccharide-stimulated murine microglial BV-2 cells. Molecular docking studies showed the strong interactions of bioactive compounds with the inducible nitric oxide synthase (iNOS) protein, revealing the potential mechanism of NO inhibition of bioactive compounds.

Hypatulone A, a Homoadamantane-Type Acylphloroglucinol with an Intricately Caged Core from Hypericum patulum.

Hypatulone A (1), an acylphloroglucinol possessing an unprecedented homoadamantane architecture based on a tricyclo-[4.3.1.13,8]-undecane core and a unique 5/5/7/6/6 pentacyclic ring system, together with its biogenetic precursor hyperbeanol B (2), was isolated from Hypericum patulum. The structure of 1 was elucidated by extensive spectroscopic analysis and electronic circular dichroism calculation. Its plausible biosynthetic pathway via Wagner-Meerwein rearrangement was proposed. 1 exhibited nitric oxide inhibitory effect on LPS-induced RAW264.7 cell line (IC50 18.8 ± 1.75 μM).

Lignan derivatives from Selaginella tamariscina and their nitric oxide inhibitory effects in LPS-stimulated RAW 264.7 cells

The chemical characterization of Selaginella tamariscina leaves resulted in the isolation of five lignanoside derivatives (1–4 and 6) and one neolignan (5). These compounds include three new lignanosides, tamariscinosides D–F (1–3), and one liriodendrin (4) that were isolated for the first time from this plant, together with two known compounds, (2R,3S)-dihydro-2-(3,5-dimethoxy-4-hydroxyphenyl)-7-methoxy-5-acetyl-benzofuran (5) and moellenoside B (6). The chemical structures of these isolated compounds were determined using 1D and 2D NMR, MS, and CD spectroscopic data, and the results were compared to data previously reported in the literatures. These compounds were also evaluated in terms of their inhibition of NO production in lipopolysaccharide (LPS)-stimulated activity in the macrophage cell line RAW 264.7. Among them, compounds 1, 2, 5, and 6 exhibited a significant inhibition with IC50 values ranging from 32.3 to 55.8μM.

A comparative investigation on the in vitro anti-inflammatory, antioxidant and antimicrobial potentials of subextracts from the aerial parts of Daphne oleoides Schreb. subsp. oleoides

Daphne oleoides Schreb. subsp. oleoides is an evergreen shrub which is known for its folkloric usage against various ailments such as arthritic and infectious diseases. The aim of the present study was to comparatively investigate the in vitro anti-inflammatory (nitric oxide inhibitory effects), antioxidant (DPPH, ABTS+ and FRAP tests) and antimicrobial activities of the extract/subextracts from the aerial parts of D. oleoides Schreb. subsp. oleoides (Thymelaeaceae). The powdered aerial parts were first extracted with methanol and then partitioned into five subextracts (n-hexane, dichloromethane (CH2Cl2), ethyl acetate (EtOAC), n-butanol and remaining water) by succesive solvent extractions. The chemical compositions of the extracts were compared with regard to their total phenolic, total flavonoid contents and fatty acid compositions. The CH2Cl2 and n-hexane extracts exerted the highest inhibitory effect on NO production (61.67±3.97% inhibition at 50μg/ml and 67.91±1.17% inhibition at 100μg/ml, respectively) of LPS-induced Raw 264.7 cells. The EtOAC subextract showed the highest antioxidant effect evaluated by DPPH (IC50: 0.35±0.12mg/ml) and FRAP (4.54±0.01mM FeSO4/mg extract) tests. The CH2Cl2 subextract was shown to contain the highest levels of flavonoids (0.837±0.035mg QUE/mg extract) and was also found to be rich in phenolics (1.063±0.011mg GAE/mg extract). Fatty acid analysis of the n-hexane extract revealed hexadecanoic acid and 9,15-octodecadienoic acids to be the major components. The n-hexane and CH2Cl2 subextracts exerted the highest antimicrobial potential.

Medicinal Plants of the Australian Aboriginal Dharawal People Exhibiting Anti-Inflammatory Activity.

Chronic inflammation contributes to multiple ageing-related musculoskeletal and neurodegenerative diseases, cardiovascular diseases, asthma, rheumatoid arthritis, and inflammatory bowel disease. More recently, chronic neuroinflammation has been attributed to Parkinson's and Alzheimer's disease and autism-spectrum and obsessive-compulsive disorders. To date, pharmacotherapy of inflammatory conditions is based mainly on nonsteroidal anti-inflammatory drugs which in contrast to cytokine-suppressive anti-inflammatory drugs do not influence the production of cytokines such as tumour necrosis factor-α or nitric oxide. However, their prolonged use can cause gastrointestinal toxicity and promote adverse events such as high blood pressure, congestive heart failure, and thrombosis. Hence, there is a critical need to develop novel and safer nonsteroidal anti-inflammatory drugs possessing alternate mechanism of action. In this study, plants used by the Dharawal Aboriginal people in Australia for the treatment of inflammatory conditions, for example, asthma, arthritis, rheumatism, fever, oedema, eye inflammation, and inflammation of bladder and related inflammatory diseases, were evaluated for their anti-inflammatory activity in vitro. Ethanolic extracts from 17 Eucalyptus spp. (Myrtaceae) were assessed for their capacity to inhibit nitric oxide and tumor necrosis factor-α production in RAW 264.7 macrophages. Eucalyptus benthamii showed the most potent nitric oxide inhibitory effect (IC50 5.57 ± 1.4 µg/mL), whilst E. bosistoana, E. botryoides, E. saligna, E. smithii, E. umbra, and E. viminalis exhibited nitric oxide inhibition values between 7.58 and 19.77 µg/mL.

Biological Activities and Stability of a Standardized Pentacyclic Triterpene EnrichedCentella asiaticaExtract

Pentacyclic triterpenes, mainly, asiatic acid, madecassic acid, asiaticoside, and madecassoside are the active constituents of Centella asiatica. A pentacyclic triterpene enriched C. asiatica extract (PRE) was prepared and standardized to contain a total pentacyclic triterpenes not less than 65% w/w. This work was focused on determination of antiinflammatory, antioxidant, and tyrosinase inhibitory activities of PRE and its stability. The PRE exhibited a satisfactory nitric oxide inhibitory effect, with an IC50 value of 64.6 µg/mL. In addition, the PRE inhibited tyrosinase enzyme activity with an IC50 value of 104.8 µg/mL. In contrast, the PRE possessed only weak antioxidant activity. The PRE was stable over a period of four months when stored as a dried powder but only in a well-closed container protected from light at 4 o C. An aqueous alcoholic solution of the PRE was stable at pH values of 5.8 and 7.0, but was not stable at a pH of 8.2. Preparations of the PRE in an aqueous solution should be performed in acidic or neutral conditions. Keywords - Centella asiatica, Pentacyclic triterpenes, Antiinflammatory, Antioxidant, Tyrosinase inhibition, Stability