Asiatic acid induces apoptosis in SK-MEL-2 human melanoma cells

Asiatic acid inhibits osteosarcoma cell migration and invasion via the AKT/Sp1/MMP1 axis

Osteosarcoma is a malignant bone tumor affecting adolescents and children. No effective treatment is currently available. Asiatic acid (AA), a triterpenoid compound found in Centella asiatica, possesses anti-tumor, anti-inflammatory, and anti-oxidant properties in various types of tumor cells. This study aims to determine whether AA exerts antitumor effects in human osteosarcoma cells. Our results indicate that AA does not influence the viability, proliferative rate, or cell cycle phase of human osteosarcoma cells under non-toxic conditions. AA suppressed osteosarcoma cell migration and invasion by down-regulating matrix metalloproteinase 1 (MMP1) expression. Data in the TNMplot database suggested MMP1 expression was higher in osteosarcoma than in normal tissues, with associated clinical significance observed in osteosarcoma patients. Overexpression of MMP1 in osteosarcoma cells reversed the AA-induced suppression of cell migration and invasion. AA treatment decreased the expression of specificity protein 1 (Sp1), while Sp1 overexpression abolished the effect of AA on MMP1 expression and cell migration and invasion. AA inhibited AKT phosphorylation, and treatment with a PI3K inhibitor (wortmannin) increased the anti-invasive effect of AA on osteosarcoma cells via the p-AKT/Sp1/MMP1 axis. Thus, AA exhibits the potential for use as an anticancer drug against human osteosarcoma.

Investigating the proliferative inhibition of HepG2 cells by exosome-like nanovesicles derived from Centella asiatica extract through metabolomics

Nano-particles demonstrating excellent anticancer properties have gradually found application in cancer therapy. However, their widespread use is impeded by their potential toxicity, high cost, and the complexity of the preparation process. In this study, we achieved exosome-like Centella asiatica-derived nanovesicles (ADNVs) through a straightforward juicing and high-speed centrifugation process. We employed transmission electron microscopy and nanoparticle flow cytometry to characterize the morphology, diameter, and stability of the ADNVs. We evaluated the in vitro anticancer effects of ADNVs using Cell Counting Kit-8 and apoptosis assays. Through sequencing and bicinchoninic acid protein analysis, we discovered the abundant presence of proteins and microRNAs in ADNVs. These microRNAs can target various diseases such as cancer and infection. Furthermore, we demonstrated the effective internalization of ADNVs by HepG2 cells, resulting in an increase in reactive oxygen species levels, mitochondrial damage, cell cycle arrest at the G1 phase, and apoptosis. Finally, we analyzed changes in cellular metabolites post-treatment using cell metabolomics techniques. Our findings indicated that ADNVs primarily influence metabolic pathways such as amino acid metabolism and lipid biosynthesis, which are closely associated with HepG2 treatment. Our results demonstrate the potential utility of ADNVs as anticancer agents.

Synergistic Combination of Luteolin and Asiatic Acid on Cervical Cancer In Vitro and In Vivo

Cervical cancer is an important issue globally because it is the second most common gynecological malignant tumor and conventional treatment effects have been shown to be limited. Lut and AsA are plant-derived natural flavonoid and triterpenoid products that have exhibited anticancer activities and can modulate various signaling pathways. Thus, the aim of the present study was to evaluate whether Lut combined with AsA could enhance the anticancer effect to inhibit cervical cancer cell proliferation and examine the underlying molecular mechanisms in vitro and in vivo. The results of a CCK-8 assay showed that Lut combined with AsA more effectively inhibited the proliferation of CaSki and HeLa cells than Lut or AsA treatment alone. Lut combined with AsA caused apoptosis induction and sub-G1-phase arrest in CaSki and HeLa cells, as confirmed by flow cytometry, mitoROS analysis, antioxidant activity measurement and western blot assay. In addition, Lut combined with AsA significantly inhibited the cell migration ability of CaSki and HeLa cells in a wound-healing assay. Furthermore, Lut combined with AsA induced apoptosis and inhibited migration through downregulated PI3K/AKT (PI3K, AKT and p70S6K), JNK/p38 MAPK and FAK (integrin β1, paxillin and FAK) signaling and upregulated ERK signaling. In an in vivo study, Lut combined with AsA markedly inhibited cervical cancer cell-derived xenograft tumor growth. Collectively, the present study showed that Lut combined with AsA may be used as an anticancer agent to improve the prognosis of cervical cancer. Indeed, with additional research to develop standardized dosages, Lut and AsA combination therapy could also be applied in clinical medicine.

Effect of acetone fraction of Ottelia alismoides on the G2/M cell cycle arrest and apoptosis in the human carcinoma cell lines

ETHNOPHARMACOLOGICAL RELEVANCE

The North-eastern parts of India have immense therapeutic floras, Ottelia alismoides is an aquatic plant that has been in use for a long time in traditional medicine for treating diseases like cancer, tuberculosis, diabetes, febrifuge, hemorrhoids, and rubefacient. In lung and skin carcinoma cells with a high rate of proliferation and metastasis including drug resistance and non-specific target activity, generates important challenges towards their treatment strategy. Thus, finding novel therapeutic targets to treat lung and skin cancer progression is essential to enhance the patients' survival with treatment.

AIM OF THE STUDY

The purpose of this study was to evaluate the apoptotic potential of acetone extract of O. alismoides (L.) Pers. (OA-AC) and to identify the compounds responsible for this effect, HRLC-MS-QTOF analysis of the extract has been undertaken along with in-silico molecular docking analysis of the identified compounds.

MATERIALS AND METHODS

A549 and A431 cells were treated with acetone extract of O. alismoides (OA-AC) at 24 h and 48 h exposure and cell cycle phase distribution was evaluated and also apoptosis induction activity was evaluated by OA-EtBr staining and Mitochondrial outer membrane potential assay. Western blotting was performed for the evaluation of apoptotic protein expression. At last, the HR-LCMS of OA-AC was analyzed to identify the compounds responsible for the apoptotic activity of the extract.

RESULTS

The cell cycle phase distribution analysis in A549 and A431 cells at 24hrs exposure with 10 μg/mL and 25 μg/mL of OA-AC showed a potent arrest or blockage at the G2/M phase of the cell cycle with reduced expression of cyclin B and p-Cdc2. At 48 h exposure, apoptosis was observed in these cancer cells with elevated expression of Bax, p21 and cleaved caspase 3 and reduced expression of the Bcl2.

CONCLUSION

AO-EtBr staining of these cancer cells reveals that the death induced by OA-AC was apoptotic in nature with depolarization of mitochondrial membrane due to loss or damage of the mitochondrial membrane. The HRLC-MS-QTOF analysis of OA-AC depicted 14 major isolable compounds and molecular docking analysis displayed 4 compounds that might act as an inhibitor of cyclin B for G2/M phase arrest that leads to apoptotic induction in the cells.

Probing Pharmaceutical Strategies to Promote the Skin Delivery of Asiatic Acid from Hydrogels: Enhancement Effects of Organic Amine Counterions, Chemical Enhancers, and Microneedle Pretreatment

Asiatic acid (AA) is a pentacyclic triterpene isolated from Centella asiatica, holding great promise for treating a variety of skin disorders. However, the dermal application of AA is limited by its poor solubility and permeability. This study aimed to identify a hydrogel formulation for AA and improve its skin penetration by various penetration enhancement methods. Four kinds of hydrogel bases were selected to prepare the AA hydrogel, in which different organic amines and chemical enhancers were incorporated in combination with microneedle pretreatment. The results showed that AA had good release profiles in the presence of hyaluronic acid as the hydrogel base and organic amines as the counter-ions. Diethylamine and Span 80 could promote drug penetration into the skin, and pretreatment with microneedles could further increase the drug permeability. In conclusion, the optimized hyaluronic acid hydrogel has great potential for use in the topical delivery of AA, and its penetration via the skin can be further improved by different pharmaceutical approaches.

Transferrin-modified nanoparticles for targeted delivery of Asiatic acid to glioblastoma cells

AIMS

Glioblastoma (GBM) is the most common and deadliest type of brain cancer, and the current therapeutic options are not curative, imposing the need for novel strategies. Asiatic acid (AA) is a natural compound and has been explored due to its anti-glioma activity and lower toxicity to healthy tissues compared with conventional chemotherapeutic agents. However, its poor water-solubility is an obstacle for clinical application. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were proposed in this work for Asiatic acid (AA) delivery.

MAIN METHODS

A central composite design was implemented to optimize the NPs, and their surface was further modified with transferrin (Tf), for targeted delivery to GBM cells. The anti-glioma activity of the NPs was studied in vitro using human GBM cells and immortalized human astrocytes.

KEY FINDINGS

The NPs exhibited a mean size smaller than 200 nm, with low polydispersity and negative zeta potential, indicating their suitability for brain tumor delivery. The NPs also exhibited high encapsulation efficiency and maintained a slow and controlled release of AA for 20 days. In vitro cell studies showed that NPs were able to maintain the anti-glioma activity of the natural compound and that the surface modification with Tf molecules was able to increase the cellular uptake in GBM cells, enhancing their selectivity and decreasing toxicity in healthy cells.

SIGNIFICANCE

Overall, this work provided guidance for designing brain-targeting delivery systems of natural compounds.

Dianthi herba: a comprehensive review of its botany, traditional use, phytochemistry, and pharmacology

Dianthi herba (called “Qumai” in Chinese) is the dried aerial part of Dianthus superbus L. and Dianthus chinensis L. The species are mainly distributed in the temperate and warm temperate regions in the northern hemisphere, and some regions in Africa and Oceania, as well as South America. However, the distribution pattern of Dianthi herba has not been reviewed. In this review, we summarize the research progress on the botany, traditional use, phytochemistry, pharmacology, toxicology, and clinical applications of Dianthi herba. Approximately 194 chemical compounds have been identified and isolated from Dianthi herba, the most important being triterpenoid saponins, flavonoids, and volatile oil compounds. These compounds possess antiviral, anticancer, antioxidant, and antimicrobial properties, inter alia. Further studies should be carried out on Dianthi herba to elucidate more of its active principles and their mechanisms of action.

In vitro anticancer activity of a pentacyclic triterpenoid via the mitochondrial pathway in bone-invasive oral squamous cell carcinoma

Context:

Oral cancer is the most dreadful cancer worldwide with a 5-year survival rate of approximately 50%. Anticancer therapies such as chemotherapy and radiotherapy result in severe side effects.

Aim:

We aimed to evaluate the in vitro anticancer activity of Asiatic acid (AA) on bone-invasive oral squamous cell carcinoma (BHY) cell line.

Settings and Design:

This was an in vitro laboratory setting.

Materials and Methods:

BHY cell lines were used for the experiment. Confocal microscopy was used to observe cellular alterations. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the IC50 concentration of AA and flow cytometry to analyze the percentage of cells in each phase of the cell cycle post treatment. Immunoblot assays and semiquantitative reverse transcriptase-polymerase chain reaction (rt-PCR) were used to study the expression level of genes involved.

Statistical Analysis Used:

Student's t-test and one-way analysis of variance were used for statistical analysis.

Results:

IC50 concentration of AA was 15.6 μM. On flow cytometry analysis, treatment with 15.6 μM and 31.25 μM of AA for 24 h increased the percentage of cells in the G2/M phase to 45.63% and 53.12%, respectively, compared to 9.62% in control group. Immunoblot analysis and semiquantitative rt-PCR demonstrated an upregulation of p53, cyclin-dependent kinase inhibitors (p21 and p27), caspase-3, caspase-9, cytochrome c and Bax in a time-dependent manner and downregulation of cyclins and anti-apoptotic protein Bcl-2 (**P < 0.05, ***P < 0.001 versus control) post AA treatment.

Conclusion:

AA induces apoptosis via the mitochondrial-dependent pathway and causes cell cycle arrest at the G2/M phase in BHY cell line.

Molecular docking analysis of flupenthixol and desmethylastemizole with the apoptotic regulator proteins CFLAR and TRAF2 linked to lung carcinoma

It is known that molecular changes in apoptotic genes due to mutation may cause disruption of apoptotic pathway resulting in an abrupt increase in cell proliferation. Therefore, it is of interest to identify compounds that could potentially replenish the changes in the apoptotic pathway, resulted from mutation. The gene network analysis using the Network Analyzer Plugin of Cytoscape (3.5.1) shows CFLAR and TRAF2 as influential genes in the apoptotic pathway. Mutation in these genes brings loss in apoptotic property of a cell and thus increases the cell proliferating activity. Thus, data on the molecular docking analysis of four natural compounds from Ottelia alismoides (L.) Pers with the two target proteins were reported. Flupenthixol and desmethylastemizole was found to be two efficient ligand molecules based on ligand-target interaction. In stereochemical quality assessment, the Ramachandran plot analysis of receptors indicates the better stereochemical characteristics for receptor-ligand interaction.

Molecular docking and simulation studies of phytocompounds derived from Centella asiatica and Andrographis paniculata against hexokinase II as mitocan agents

Hexokinase II (HK2), a glycolytic enzyme is commonly overexpressed in most cancer types. The overexpression of HK2 is reported to promote the survival of cancer cells by facilitating the constant ATP generation and protecting the cancer cell against apoptotic cell death. Hence, HK2 is considered as potential target of many mitochondria targeting anticancerous agents (referred to as mitocans). Most of the existing mitocans are synthetic and hence such compounds are observed to exhibit adverse effects, witnessed through many experimental outcomes. These limitations necessitates hunting for an alternative source of mitocans with minimum/no side effects. The need for an alternative therapy points towards the ethnomedicinal herbs, known for their minimal side effects and effectiveness. Henceforth recent studies have put forth the effort to utilize anticancer herbs in formulating naturally derived mitocans as an add-on to improve cancer therapeutics. So, our study aims to explore the HK2 targeting potential of phytocompounds from the selected anticancerous herbs Andrographis paniculata (AP) and Centella asiatica (CA). 60 phytocompounds collectively from CA and AP were docked against HK2 and drug-likeness prediction of the selected phytocompounds was performed to screen the best possible ligand for HK2. Furthermore, the docked complexes were subjected to molecular dynamics simulations (MDS) to analyse the molecular mechanism of protein-ligand interactions. The results of the study suggest that the natural compounds asiatic acid and bayogenin (from CA) and andrographolide (from AP) can bepotential natural mitocans by targeting HK2. Further experimental studies (in-vitro and in-vivo) are required to validate the results.

Anticancer effects of asiatic acid against doxorubicin-resistant breast cancer cells via an AMPK-dependent pathway in vitro

BACKGROUND AND PURPOSE

Asiatic acid is one of the active compounds isolated from Centella asiatica and has been used to treat many diseases, including hypertension, pulmonary fibrosis, and cancer. It exhibits anticancer effects in many cancers, such as ovarian, lung and colon cancer; however, its anticancer effects in breast cancer and the underlying mechanism are not fully understood. Chemoresistance is often induced after the use of chemotherapy, and it is a challenging problem in cancer therapy. The effects of asiatic acid on chemoresistance in breast cancer have never been studied. Therefore, the aim of the present study was to examine the anticancer effects of asiatic acid in doxorubicin-resistant breast cancer MCF-7 cells.

METHODS

The cells were incubated with asiatic acid at 0-160 μM for 2-24 h. Cell viability and cytotoxicity were evaluated by 3-[4, 5-dimethyl-2-thiazolyl]-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Florescent images were taken using a confocal microscope. P-gp function and apoptosis assays were performed using flow cytometry. Caspase activity was measured with the Caspase-Glo™ Assay System. The phosphorylation and expression of relevant proteins were assessed by western blots. Molecular docking was performed and scored by AutoDock. Cellular thermal shift assay (CETSA) was applied for experimental valuation.

RESULTS

Our data demonstrated that asiatic acid induced cell death in multiple ways, including reactive oxygen species production, adenosine triphosphate (ATP) content reduction, and adaptive immunity balance via intrinsic apoptosis, AMP-activated protein kinase (AMPK), programmed death-ligand 1 (PD-L1), and indirect nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional pathways, using experimental validation and in silico analysis. Moreover, asiatic acid also enhanced the sensitivity of doxorubicin-resistant MCF-7 cells to doxorubicin by improving P-glycoprotein (P-gp) function.

CONCLUSIONS

This study provides evidence that asiatic acid has strong anticancer effects to reverse multidrug resistance and could be developed as a promising adjuvant drug for the treatment of chemoresistant cancer.

Asiatic acid inhibits angiogenesis and vascular permeability through the VEGF/VEGFR2 signaling pathway to inhibit the growth and metastasis of breast cancer in mice

Anti-angiogenic medicines have been evaluated as anticancer therapies, however, their use remains limited in clinical practice due to associated adverse effects. Asiatic acid (AA) is known to have broad-spectrum anticancer properties, however, its effects on angiogenesis in breast cancer remain to be fully established. In this study, we analyzed the inhibitory effects of AA on angiogenesis using human umbilical vein endothelial cells (HUVECs) cultured in vitro and on the growth and metastasis of a subcutaneous breast cancer 4T1 tumor model and a lung metastasis model in vivo. AA significantly inhibited HUVECs proliferation, migration, and tube formation in vitro. In vivo, AA significantly reduced the microvascular density and blood vascular permeability in breast cancer tumors and inhibited growth and lung metastasis. AA inhibited the expression of vascular endothelial growth factor (VEGF) in HUVECs and subsequently downregulated the phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) and its downstream target proteins including ERK1/2, Src, and FAK. These results indicate that AA significantly inhibits angiogenesis and blood vessel permeability through the VEGF/VEGFR2 signal axis to inhibit the growth and metastasis of breast cancer. Our data strongly demonstrate the potential applications of AA in the treatment of breast cancer.

Actions and Therapeutic Potential of Madecassoside and Other Major Constituents of Centella asiatica: A Review

Centella asiatica is a popular herb well-known for its wide range of therapeutic effects and its use as a folk medicine for many years. Its therapeutic properties have been well correlated with the presence of asiaticoside, madecassoside, asiatic and madecassic acids, the pentacyclic triterpenes. The herb has been extensively known to treat skin conditions; nevertheless, several pre-clinical and clinical studies have scientifically demonstrated its effectiveness in other disorders. Among the active constituents that have been identified in Centella asiatica, madecassoside has been the subject of only a relatively small number of scientific reports. Therefore, this review, while including other major constituents of this plant, focuses on the therapeutic potential, pharmacokinetics and toxicity of madecassoside.

Ethnobotany, phytochemistry, pharmacology, and toxicity of Centella asiatica (L.) Urban: A comprehensive review

The well-known medicinal plant Centella asiatica (L.) Urban is an Ayurvedic and traditional Chinese medicine used in the treatment of different health problems and as an edible vegetable in a regular diet. Ease of availability in the wide range of environmental conditions plus low-cost cultivation process has made the plant popular in ethno-medicinal healthcare systems. In the present review, phytochemical analysis of plant-extract and pharmacological activities of bioactive-compounds are discussed based upon the available reports to understand their therapeutic potentialities along with the mechanisms behind. The results exhibited that C. asiatica and its triterpenoids demonstrated an array of pharmacological effects and health benefits, some of which were confirmed in many preclinical and clinical studies. Those reports also provided considerable evidences in support of the principles of folk treatment in different countries. Increase and maintenance of the prospective plant secondary metabolites would provide an enriched resource of drug molecules. Development of suitable derivatives of the therapeutic compounds can give an assurance for getting more effective drug candidates with reduced side effects. The review also enumerates the application of advanced nanotechnology, toxicology, and clinical-trial reports on the plant with notes on the shortcomings in the present research and future perspectives of using this medicinal plant.

Ursolic Acid and Related Analogues: Triterpenoids with Broad Health Benefits

Ursolic acid (UA) is a well-studied natural pentacyclic triterpenoid found in herbs, fruit and a number of traditional Chinese medicinal plants. UA has a broad range of biological activities and numerous potential health benefits. In this review, we summarize the current data on the bioavailability and pharmacokinetics of UA and review the literature on the biological activities of UA and its closest analogues in the context of inflammation, metabolic diseases, including liver and kidney diseases, obesity and diabetes, cardiovascular diseases, cancer, and neurological disorders. We end with a brief overview of UA’s main analogues with a special focus on a newly discovered naturally occurring analogue with intriguing biological properties and potential health benefits, 23-hydroxy ursolic acid.

Application of Amino Acids in the Structural Modification of Natural Products: A Review

Natural products and their derivatives are important sources for drug discovery; however, they usually have poor solubility and low activity and require structural modification. Amino acids are highly soluble in water and have a wide range of activities. The introduction of amino acids into natural products is expected to improve the performance of these products and minimize their adverse effects. Therefore, this review summarizes the application of amino acids in the structural modification of natural products and provides a theoretical basis for the structural modification of natural products in the future. The articles were divided into six types based on the backbone structures of the natural products, and the related applications of amino acids in the structural modification of natural products were discussed in detail.

Anti-Cancer Effects of Asiatic Acid, a Triterpene from Centilla asiatica L: A Review

BACKGROUND

Centilla asiatica L is a medicinal herb that has been widely used in folk medicine to treat various diseases. Asiatic Acid (AA), a triterpene and a known component of this herb, has been shown to display important biological activities, including anti-inflammatory, antibacterial, antidiabetic and antihyperlipidemic, neuroprotective, anxiolytic and antidepressant, hepatoprotective, pancreas protective, and cardio- protective.

OBJECTIVE

This review focuses on AA's anti-cancer effects on the basis of published literature found in a number of databases such as PubMed and Science Direct. Emphasis has been given to the mechanisms of action of its anti-cancer effect.

METHODS

A literature survey was conducted using known databases such as PubMed and Science Direct using the keywords 'Asiatic acid', pairing with 'cancer', 'tumor', 'anti-cancer effect', 'cytotoxic effect', 'anti-tumor activity', 'cell line', 'animal cancer', and 'human cancer'.

RESULTS

Findings suggest that AA exerts anti-cancer effects in several test systems through various pathways, including oxidative/antioxidant, anti-inflammatory, cytotoxicity, apoptotic cell death, necrosis, anti-angiogenesis, inhibition of proliferation and cell migration, and chemoprevention.

CONCLUSION

AA may be an effective plant-based cancer chemotherapeutic agent and a promising lead for the development of potent anticancer drugs.

Natural Agents Targeting Mitochondria in Cancer

Mitochondria are the key energy provider to highly proliferating cancer cells, and are subsequently considered one of the critical targets in cancer therapeutics. Several compounds have been studied for their mitochondria-targeting ability in cancer cells. These studies’ outcomes have led to the invention of “mitocans”, a category of drug known to precisely target the cancer cells’ mitochondria. Based upon their mode of action, mitocans have been divided into eight classes. To date, different synthetic compounds have been suggested to be potential mitocans, but unfortunately, they are observed to exert adverse effects. Many studies have been published justifying the medicinal significance of large numbers of natural agents for their mitochondria-targeting ability and anticancer activities with minimal or no side effects. However, these natural agents have never been critically analyzed for their mitochondria-targeting activity. This review aims to evaluate the various natural agents affecting mitochondria and categorize them in different classes. Henceforth, our study may further support the potential mitocan behavior of various natural agents and highlight their significance in formulating novel potential anticancer therapeutics.

Asiaticoside Antagonizes Proliferation and Chemotherapeutic Drug Resistance in Hepatocellular Carcinoma (HCC) Cells

Background

Hepatocellular carcinoma (HCC) is the fifth most prevalent malignant tumor in China after lung cancer, gastric cancer, esophageal cancer, and breast cancer, and has a high mortality rate. Though there are a series of therapeutic strategies is now available for HCC in clinical practice, the 5-year survival rate after surgery is still low. In addition, multi-drug resistance (MDR) is one of the most important factors responsible for the low survival rate and poor therapy response in HCC. Hence, novel treatment strategies and molecules for HCC need to be developed.

Material/Methods

We assessed the effect of asiaticoside, a natural product derived from Centella asiatica (L.) Urban, on HCC cell proliferation and drug resistance.

Results

Our data indicated that asiaticoside significantly inhibited the proliferation of HCC cell lines QGY-7703 and Bel-7402 in a dose- and time-dependent manner. Moreover, asiaticoside significantly induced apoptosis in QGY-7703 and Bel-7402 cells. Treatment with asiaticoside also caused G1 cell cycle arrest in QGY-7703 and Bel-7402 cells. Western blot assay results indicated that the mechanism underlying the effects of asiaticoside involves inhibiting the activity of the PI3K/Akt and MAPK/ERK pathways. Furthermore, asiaticoside significantly antagonized P-gp-mediated MDR in HCC cells.

Conclusions

Our results suggest that asiaticoside has the potential to be applied in the treatment of HCC patients, but further evidence is needed to confirm our results, particularly in vivo efficacy.

Synthesis and Cytotoxic Activity of Novel C-23-Modified Asiatic Acid Derivatives

We selectively oxidized the C-23 hydroxyl group in an asiatic acid (AA) derivative and then, for the first time with AA, modification of the C-23 carboxyl group was conducted to synthesize a series of new AA derivatives. The evaluation of their cytotoxic activities against two human cancer cell lines (SKOV-3 and HCT116) using the MTT assay in vitro revealed a distinctive structure activity relationship (SAR) associated with the intramolecular hydrogen bonding of the amide moiety at C-23. According to the established SAR, the cytotoxic activities of four promising compounds were then evaluated against MCF-7, A549, A2780, HepG2 and HL-60 cancer cell lines. Compound 10 had the best cytotoxic activity among all tested derivatives in the HL-60 cell line, giving IC₅₀ = 0.47 μM, while showing no cytotoxic effect against human normal cells (HUVEC).

RGD-decorated solid lipid nanoparticles enhance tumor targeting, penetration and anticancer effect of asiatic acid

Aim: Asiatic acid (AA) is a promising anticancer agent, however, its delivery to glioblastoma is a major challenge. This work investigates the beneficial therapeutic efficacy of RGD-conjugated solid lipid nanoparticles (RGD-SLNs) for the selective targeting of AA to gliblastoma. Materials & methods: AA-containing RGD-SLNs were prepared using two different PEG-linker size. Targetability and efficacy were tested using monolayer cells and spheroid tumor models. Results: RGD-SLNs significantly improved cytotoxicity of AA against U87-MG monolayer cells and enhanced cellular uptake compared with non-RGD-containing SLNs. In spheroid models, AA-containing RGD-SLNs showed superior control in tumor growth, improved cytotoxicity and enhanced spheroid penetration when compared with AA alone or non-RGD-containing SLNs. Conclusion: This study illustrates the potential of AA-loaded RGD-SLNs as efficacious target-specific treatment for glioblastoma.

Asiatic acid prevents renal fibrosis in UUO rats via promoting the production of 15d-PGJ2, an endogenous ligand of PPAR-γ

Renal fibrosis is an inevitable outcome of all kinds of progressive chronic kidney disease (CKD). Recently, asiatic acid (AA), a triterpenoid compound from Chinese medicine Centella asiatica, has been found to attenuate renal fibrosis. In the current study, we explored the mechanisms underlying antifibrotic effect of AA on UUO model. SD rats and ICR mice were subjected to unilateral ureteral occlusion (UUO) surgery. Prior the surgery, rats were administered AA (10 mg·kg^-1 per day, ig) for 7 days, whereas the mice received AA (15 mg·kg^-1 per day, ig) for 3 days. UUO group displayed significant degree of renal dysfunction, interstitial fibrosis, oxidative stress, and activation of the TGF-β/Smad and Wnt/β-catenin signaling pathway in the kidney, these pathological changes were greatly ameliorated by pretreatment with AA. In addition, we found that co-treatment with GW9662, a selective PPAR-γ antagonist (1 mg·kg^-1 per day, ip) for 7 days, abolished the protective effects of AA. We further revealed that AA pretreatment did not significantly change the expression levels of PPAR-γ in the kidney, but markedly increase the plasma levels of 15d-PGJ2, an endogenous ligand of PPAR-γ. In UUO mice, pretreatment with 15d-PGJ2 (24 μg·kg^-1 per day, ip, for 7 days) produced similar protective effect as AA. Moreover, AA pretreatment upregulated the expression levels of active, nuclear-localized SREBP-1 (nSREBP-1), whereas fatostatin, a specific inhibitor of SREBP-1, decreased the expression of nSREBP-1, as well as the level of 15d-PGJ2. These results provide new insight into the antifibrotic mechanism of AA and endogenous metabolites might become a new clue for investigation of drug mechanism.

In Vivo Toxicity Study of Ethanolic Extracts of Evolvulus alsinoides & Centella asiatica in Swiss Albino Mice

AIM

We aimed to investigate several parameters after the in vivo acute and sub-acute administration of ethanolic extracts from E. alsinoides & C. asiatica.

METHODS

Malignant Ovarian Germ Cell Tumors for in vivo toxicity study guidelines 423 and 407 of Organization for Economic Co-operation and Development (OECD) were followed for acute and sub-acute toxicity assays respectively. For LD50 evaluation, a single dose of ethanolic extracts of Evolvulus alsinoides L. (EEA) and ethanolic extracts of Centella asiatica (ECA) was orally administered to mice at doses of 200, 400, 800, 1600 and 2000 mg/kg. Then the animals were observed for 72 hours. For acute toxicity evaluation, a single dose of both extracts was orally administered to mice at doses of 300, 600, 1200 and 2000 mg/kg and the animals were observed for 14 days. In the sub-acute study, the extracts were orally administered to mice for 28 days at doses of 300, 600, 1200 and 2000 mg/kg. To assess the toxicological effects, animals were closely observed on general behaviour, clinical signs of toxicity, body weight, food and water intake. At the end of the study, it was performed biochemical and hematological evaluations, as well as histopathological analysis from the following organs: brain, heart, liver, and kidney.

RESULTS

The oral administration of E. alsinoides and C. asiatica ethanolic extracts, i.e. EEA 300, EEA 600, EEA 1200, EEA 2000, ECA 300, ECA 600, ECA 1200 & ECA 2000 mg/kg doses showed no moral toxicity effect in LD50, acute and sub-acute toxicity parameters.

CONCLUSION

In this study, we had found that E. alsinoides & C. asiatica extract at different doses cause no mortality in acute and sub-acute toxicity study. Also, histopathology of kidney, liver, heart, and brain showed no alterations in tissues morphology.

Pharmacological Properties, Molecular Mechanisms, and Pharmaceutical Development of Asiatic Acid: A Pentacyclic Triterpenoid of Therapeutic Promise

Asiatic acid (AA) is a naturally occurring aglycone of ursane type pentacyclic triterpenoids. It is abundantly present in many edible and medicinal plants including Centella asiatica that is a reputed herb in many traditional medicine formulations for wound healing and neuropsychiatric diseases. AA possesses numerous pharmacological activities such as antioxidant and anti-inflammatory and regulates apoptosis that attributes its therapeutic effects in numerous diseases. AA showed potent antihypertensive, nootropic, neuroprotective, cardioprotective, antimicrobial, and antitumor activities in preclinical studies. In various in vitro and in vivo studies, AA found to affect many enzymes, receptors, growth factors, transcription factors, apoptotic proteins, and cell signaling cascades. This review aims to represent the available reports on therapeutic potential and the underlying pharmacological and molecular mechanisms of AA. The review also also discusses the challenges and prospects on the pharmaceutical development of AA such as pharmacokinetics, physicochemical properties, analysis and structural modifications, and drug delivery. AA showed favorable pharmacokinetics and found bioavailable following oral or interaperitoneal administration. The studies demonstrate the polypharmacological properties, therapeutic potential and molecular mechanisms of AA in numerous diseases. Taken together the evidences from available studies, AA appears one of the important multitargeted polypharmacological agents of natural origin for further pharmaceutical development and clinical application. Provided the favorable pharmacokinetics, safety, and efficacy, AA can be a promising agent or adjuvant along with currently used modern medicines with a pharmacological basis of its use in therapeutics.

Combination of Asiatic Acid and Naringenin Modulates NK Cell Anti-cancer Immunity by Rebalancing Smad3/Smad7 Signaling

Transforming growth factor β1 (TGF-β1) plays a promoting role in tumor growth via a mechanism associated with hyperactive Smad3 and suppressed Smad7 signaling in the tumor microenvironment. We report that retrieving the balance between Smad3 and Smad7 signaling with asiatic acid (AA, a Smad7 inducer) and naringenin (NG, a Smad3 inhibitor) effectively inhibited tumor progression in mouse models of invasive melanoma (B16F10) and lung carcinoma (LLC) by promoting natural killer (NK) cell development and cytotoxicity against cancer. Mechanistically, we found that Smad3 physically bound Id2 and IRF2 to suppress NK cell production and NK cell-mediated cytotoxicity against cancer. Treatment with AA and NG greatly inhibited Smad3 translation and phosphorylation while it restored Smad7 expression, and, therefore, it largely promoted NK cell differentiation, maturation, and cytotoxicity against cancer via Id2/IRF2-associated mechanisms. In contrast, silencing Id2 or IRF2 blunted the protective effects of AA and NG on NK cell-dependent anti-cancer activities. Thus, treatment with AA and NG produced an additive effect on inactivating TGF-β1/Smad3 signaling, and, therefore, it suppressed melanoma and lung carcinoma growth by promoting NK cell immunity against cancer via a mechanism associated with Id2 and IRF2.

Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo

Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear.

Methods

In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined.

Results

We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling.

Conclusion

For the first time, this study reveals that AA-PMe acts as a potent VEGFR2 kinase inhibitor and exerts powerful antiangiogenic activity, suggesting it to be a promising therapeutic candidate for further research.

Asiatic acid inhibits proliferation, migration and induces apoptosis by regulating Pdcd4 via the PI3K/Akt/mTOR/p70S6K signaling pathway in human colon carcinoma cells

Previous studies have demonstrated that asiatic acid (AA), the major component of Centella asiatica, is able to meditate cytotoxic and anticancer effects on various types of carcinoma cells. In order to investigate the molecular mechanism that underlies the antitumor effect of AA, the present study investigated the effects of AA on proliferation, migration and apoptosis of SW480 and HCT116 colon cancer cells. Viability and changes in cell morphology in the cells were assessed by MTT assay and transmission electron microscopy, respectively. Colony formation analysis was used to observe proliferation of the single cell, and migratory ability of the cells was assessed by performing Transwell migration assay. Hoechst 33342 nuclear staining and flow cytometry were used to assess apoptosis in colon carcinoma cells. The expression of proteins associated with the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/p70S6K signaling pathway and epithelial-mesenchymal transition (EMT) marker were analyzed by western blotting. The present study revealed that proliferation and migration of colon carcinoma cells were inhibited by AA in a dose-dependent and time-dependent manner. Numerous apoptotic bodies were observed, and G₂/M and S phase progression were delayed in colon cancer cells treated with AA, but not in the control group. A number of phosphorylated proteins, including PI3K, Akt (Ser⁴⁷³), mTOR, ribosomal protein S6 kinase (p70S6K) downregulated, while the expression of Pdcd4 was upregulated following treatment with AA. Additionally, AA affects expression of EMT markers in a dose-dependent manner. On the basis of these results, it was concluded that AA inhibited proliferation, migration and induced apoptosis of colon cancer cells by regulating Pdcd4 via the PI3K/Akt/mTOR/p70S6K signaling pathway. These observations suggest that AA may be a potential therapeutic agent for the treatment of colon carcinoma.

Anti inflammatory effect of asiaticoside on human umbilical vein endothelial cells induced by ox-LDL

Early diagnosis and changes associated with atherosclerosis are crucial in clinical medicine. However, atherosclerosis is a multifactorial disease. Asiaticoside (AA), a triterpenoid derived from Centella asiatica, has anti-inflammatory activity. Endothelium-derived nitric oxide is important in modulating vascular tone in a distinct vessel size-dependent manner; it plays a dominant role in conduit arteries and endothelium-dependent hyperpolarisation in resistance vessels. This study evaluated the effects of AA administration on human umbilical endothelial cells with oxidised low-density lipoprotein-induced inflammation. We measured the levels of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Our results indicated that 10-30 μM AA modulated endothelial hyper permeability, adenosine triphosphate levels, ICAM-1 expression, VCAM-1 expression, E-selectin levels, and PECAM-1 expression to 90% (p < 0.005), 80% (p < 0.05), 105% (p < 0.01), 65% (p < 0.005), 70% (p < 0.05), and 105% (p < 0.01), respectively. Taken together, our data suggest that AA inhibits the augmentation of endothelial permeability, thus preventing the early events of atherosclerosis.

Pharmacological Review on Asiatic Acid and Its Derivatives: A Potential Compound

Natural triterpenes represent a group of pharmacologically active and structurally diverse organic compounds. The focus on these phytochemicals has been enormous in the past few years, worldwide. Asiatic acid (AA), a naturally occurring pentacyclic triterpenoid, is found mainly in the traditional medicinal herb Centella asiatica. Triterpenoid saponins, which are the primary constituents of C. asiatica, are commonly believed to be responsible for their extensive therapeutic actions. Published research work has described the molecular mechanisms underlying the various biological activities of AA and its derivatives, which vary for each chronic disease. However, a compilation of the various pharmacological properties of AA has not yet been done. Herein, we describe in detail the pharmacological properties of AA and its derivatives that inhibit multiple pathways of intracellular signaling molecules and transcription factors that are involved in the various stages of chronic diseases. Furthermore, the pharmacological activities of AA were compared with two natural compounds: curcumin and resveratrol. This review summarizes the research on AA and its derivatives and helps to provide future directions in the area of drug development.

Asiatic acid abridges pre-neoplastic lesions, inflammation, cell proliferation and induces apoptosis in a rat model of colon carcinogenesis

The utmost aim of this present study was to investigate the anti-inflammatory, antiproliferative and proapoptotic potential of Asiatic acid (AA) on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in experimental rats. Rats were divided into six groups and received modified pellet diet for 32 weeks. Group 1 served as control rats. Group 2 received AA (4 mg/kg b.w. p.o.). Group 3-6 rats received 15 DMH (20 mg/kg b.w., s.c.) injections once a week starting from the 4th week. Besides DMH, rats received AA (4 mg/kg b.w. p.o.) in group 4 starting 2 weeks before carcinogen treatment till the end of the last DMH; group 5 starting 2 days after last DMH till the end of the experiment; and group 6 throughout the experiment. Pre-neoplastic lesions, xenobiotic metabolizing enzymes, inflammation, cell proliferation and apoptotic markers were analysed in our study. Our results ascertained AA supplementation to DMH-exposed rats significantly decreased the incidence of aberrant crypt foci (ACF) and phase I xenobiotic enzymes; and increased the phase II xenobiotic enzymes and mucin content as compared to DMH-alone-exposed rats. Moreover the increased expressions of mast cells, argyrophilic nucleolar organizer regions (AgNORs), proliferating cell nuclear antigen (PCNA) and cyclin D1 observed in the DMH-alone-exposed rats were reverted and were comparable with those of the control rats, when treated with AA. Concordantly AA also induced apoptosis by downregulating the expression of Bcl-2 and upregulating Bax, cytochrome c, caspase-3 and -9 in the DMH-alone-exposed rats. Thus AA was able to inhibit DMH-induced colon carcinogenesis by detoxifying the carcinogen, decreasing the preneoplastic lesions by virtue of its anti-inflammatory, antiproliferative and proapoptotic effects. Therefore our findings suggest that AA could be used as an effective chemopreventive agent against DMH induced colon carcinogenesis.

Asiatic acid protects against hepatic ischemia/reperfusion injury by inactivation of Kupffer cells via PPARγ/NLRP3 inflammasome signaling pathway

Hepatic ischemia/reperfusion (I/R) contributes to major complications in clinical practice affecting perioperative morbidity and mortality. Recent evidence suggests the key role of nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammaosme activation on the pathogenesis of I/R injury. Asiatic acid (AA) is a pentacyclic triterpene derivative presented with versatile activities, including antioxidant, anti-inflammation and hepatoprotective effects. This study was designed to determine whether AA had potential hepatoprotective benefits against hepatic I/R injury, as well as to unveil the underlying mechanisms involved in the putative effects. Mice subjected to warm hepatic I/R, and Kupffer cells (KCs) or RAW264.7 cells challenged with lipopolysaccharide (LPS)/H₂O₂, were pretreated with AA. Administration of AA significantly attenuated hepatic histopathological damage, global inflammatory level, apoptotic signaling level, as well as NLRP3 inflammasome activation. These effects were correlated with increased expression of peroxisome proliferator-activated receptor gamma (PPARγ). Conversely, pharmacological inhibition of PPARγ by GW9662 abolished the protective effects of AA on hepatic I/R injury and in turn aggravated NLRP3 inflammasome activation. Activation of NLRP3 inflammasome was most significant in nonparenchymal cells (NPCs). Depletion of KCs by gadolinium chloride (GdCl3) further attenuated the detrimental effects of GW9662 on hepatic I/R as well as NLRP3 activation. In vitro, AA concentration-dependently inhibited LPS/H₂O₂-induced NLRP3 inflammaosome activation in KCs and RAW264.7 cells. Either GW9662 or genetic knockdown of PPARγ abolished the AA-mediated inactivation of NLRP3 inflammasome. Mechanistically, AA attenuated I/R or LPS/H₂O₂-induced ROS production and phosphorylation level of JNK, p38 MAPK and IκBα but not ERK, a mechanism dependent on PPARγ. Finally, AA blocked the deleterious effects of LPS/H₂O₂-induced macrophage activation on hepatocyte viability in vitro, and improved survival in a lethal hepatic I/R injury model in vivo. Collectively, these data suggest that AA is effective in mitigating hepatic I/R injury through attenuation of KCs activation via PPARγ/NLRP3 inflammasome signaling pathway.

Centella asiatica modulates cancer cachexia associated inflammatory cytokines and cell death in leukaemic THP-1 cells and peripheral blood mononuclear cells (PBMC's)

Background

Cancer cachexia is associated with increased pro-inflammatory cytokine levels. Centella asiatica (C. asiatica) possesses antioxidant, anti-inflammatory and anti-tumour potential. We investigated the modulation of antioxidants, cytokines and cell death by C. asiatica ethanolic leaf extract (C_LE) in leukaemic THP-1 cells and normal peripheral blood mononuclear cells (PBMC’s).

Methods

Cytotoxcity of C_LE was determined at 24 and 72 h (h). Oxidant scavenging activity of C_LE was evaluated using the 2, 2-diphenyl-1 picrylhydrazyl (DPPH) assay. Glutathione (GSH) levels, caspase (−8, −9, −3/7) activities and adenosine triphosphate (ATP) levels (Luminometry) were then assayed. The levels of tumour necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β and IL-10 were also assessed using enzyme-linked immunosorbant assay.

Results

C_LE decreased PBMC viability between 33.25–74.55% (24 h: 0.2–0.8 mg/ml C_LE and 72 h: 0.4–0.8 mg/ml C_LE) and THP-1 viability by 28.404% (72 h: 0.8 mg/ml C_LE) (p < 0.0001). Oxidant scavenging activity was increased by C_LE (0.05–0.8 mg/ml) (p < 0.0001). PBMC TNF-α and IL-10 levels were decreased by C_LE (0.05–0.8 mg/ml) (p < 0.0001). However, PBMC IL-6 and IL-1β concentrations were increased at 0.05–0.2 mg/ml C_LE but decreased at 0.4 mg/ml C_LE (p < 0.0001). In THP-1 cells, C_LE (0.2–0.8 mg/ml) decreased IL-1β and IL-6 whereas increased IL-10 levels (p < 0.0001). In both cell lines, C_LE (0.05–0.2 mg/ml, 24 and 72 h) increased GSH concentrations (p < 0.0001). At 24 h, caspase (−9, −3/7) activities was increased by C_LE (0.05–0.8 mg/ml) in PBMC’s whereas decreased by C_LE (0.2–0.4 mg/ml) in THP-1 cells (p < 0.0001). At 72 h, C_LE (0.05–0.8 mg/ml) decreased caspase (−9, −3/7) activities and ATP levels in both cell lines (p < 0.0001).

Conclusion

In PBMC’s and THP-1 cells, C_LE proved to effectively modulate antioxidant activity, inflammatory cytokines and cell death. In THP-1 cells, C_LE decreased pro-inflammatory cytokine levels whereas it increased anti-inflammatory cytokine levels which may alleviate cancer cachexia.

Asiatic acid inhibits lung cancer cell growth in vitro and in vivo by destroying mitochondria

Asiatic acid (AA), a pentacyclic triterpene found in Centella asiatica, displays significant anti-proliferative effects on cancer cells in vitro although the underlying mechanism of this effect remains unknown. This study investigated the efficacy and mechanism of action of AA against lung cancer both in vivo and in vitro. Using the MTT assay, AA was found to induce apoptosis in a dose- and time-dependent manner, an effect enhanced by pretreatment with an autophagy inhibitor. It also elevated expression of microtubule-associated protein 1 light chain 3 (LC3) and decreased the expression of p62. Furthermore, exposure to AA resulted in collapse of the mitochondrial membrane potential and generation of reactive oxygen species (ROS), suggesting mitochondria are the target of AA. In the mouse lung cancer xenograft model, oral administration of AA significantly inhibited tumor volume and weight accompanied by significant apoptosis of lung cancer cells. In addition, it led to a significant decrease in the expression of proliferating cell nuclear antigen (PCNA). In summary, the results show that AA significantly reduces lung cancer cell growth both in vitro and in vivo and that the associated apoptosis is mediated through mitochondrial damage.

A novel synthetic Asiatic acid derivative induces apoptosis and inhibits proliferation and mobility of gastric cancer cells by suppressing STAT3 signaling pathway

Activation of the transcription factor, signal transducers and activators of transcription 3 (STAT3), has been linked to the proliferation and migration of a variety of human cancer cells. These actions occur via the upregulation or downregulation of cell survival and tumor suppressor genes, respectively. Importantly, agents that can suppress STAT3 activation have the potential for use in the prevention and treatment of various cancers. In this study, an Asiatic acid (AA) derivative, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-l-proline methyl ester (AA-PMe), is reported to dose dependently suppress constitutive STAT3 activation in gastric cancer cells. This inhibition was mediated by blockade of Janus-activated kinase 2. Additionally, AA-PMe regulated the expression of STAT3-modulated gene products, including cyclin D1, Bax, Bcl-2, c-Myc, and matrix metalloproteinase (MMP)-2 and MMP-9. Finally, transfection with both a STAT3 mimic and an inhibitor reversed the AA-PMe-driven modulation of STAT3 downstream gene products. Overall, these results suggest that AA-PMe is a novel blocker of STAT3 activation and has the potential for the prevention and treatment of gastric cancer.

Asiatic acid exerts anticancer potential in human ovarian cancer cells via suppression of PI3K/Akt/mTOR signalling

Context Asiatic acid, a triterpenoid compound extracted from the tropical medicinal plant Centella asiatica (Family: Apiaceae), has exhibited various biological activities. Objective This study was performed to investigate the cytotoxic effects of asiatic acid on human ovarian cancer cells. Materials and methods SKOV3 and OVCAR-3 ovarian cancer cells were exposed to different concentrations of asiatic acid (10-100 μg/mL) for 72 or 48 h. Cell viability, colony formation, cell cycle distribution, apoptotic response were examined. Involvement of the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway was tested. Results At the concentration of 40 μg/mL, asiatic acid caused about 50% reduction in the viability of ovarian cancer cells, but had little effect on the viability of normal human ovarian epithelial cells. Asiatic acid at 10 μg/mL reduced colony formation of ovarian cancer cells by 25-30%. Asiatic acid-treated cells showed a cell cycle arrest at the G0/G1 phase and 7- to 10-fold increase in apoptosis. The phosphorylation levels of PI3K, Akt and mTOR were remarkably lower in asiatic acid-treated cells. Overexpression of constitutively active Akt partially reversed the cytotoxic effects of asiatic acid, as evidenced by increased cell viability and colony formation. Furthermore, knockdown of Akt mimicked the growth-suppressive activity of asiatic acid. Discussion and conclusion These results provide first the evidence for the anticancer potential of asiatic acid in ovarian cancer cells, partially via inactivation of the PI3K/Akt/mTOR pathway. Asiatic acid may represent a potential therapeutic agent for ovarian cancer.

Asiatic acid uncouples respiration in isolated mouse liver mitochondria and induces HepG2 cells death

Asiatic acid, one of the triterpenoid components isolated from Centella asiatica, has received increasing attention due to a wide variety of biological activities. To date, little is known about its mechanisms of action. Here we examined the cytotoxic effect of asiatic acid on HepG2 cells and elucidated some of the underlying mechanisms. Asiatic acid induced rapid cell death, as well as mitochondrial membrane potential (MMP) dissipation, ATP depletion and cytochrome c release from mitochondria to the cytosol in HepG2 cells. In mitochondria isolated from mouse liver, asiatic acid treatment significantly stimulated the succinate-supported state 4 respiration rate, dissipated the MMP, increased Ca(2+) release from Ca(2+)-loaded mitochondria, decreased ATP content and promoted cytochrome c release, indicating the uncoupling effect of asiatic acid. Hydrogen peroxide (H2O2) produced by succinate-supported mitochondrial respiration was also significantly inhibited by asiatic acid. In addition, asiatic acid inhibited Ca(2+)-induced mitochondrial swelling but did not induce mitochondrial swelling in hyposmotic potassium acetate medium which suggested that asiatic acid may not act as a protonophoric uncoupler. Inhibition of uncoupling proteins (UCPs) or blockade of adenine nucleotide transporter (ANT) attenuated the effect of asiatic acid on MMP dissipation, Ca(2+) release, mitochondrial respiration and HepG2 cell death. When combined inhibition of UCPs and ANT, asiatic acid-mediated uncoupling effect was noticeably alleviated. These results suggested that both UCPs and ANT partially contribute to the uncoupling properties of asiatic acid. In conclusion, asiatic acid is a novel mitochondrial uncoupler and this property is potentially involved in its toxicity on HepG2 cells.

Design, synthesis and evaluation of antitumor activity of new rotundic acid acylhydrazone derivatives

In light of the important antitumor activity of acylhydrazone compounds and based on our previous study, 18 new rotundic acid (RA) acylhydrazone derivatives were synthesized. All of the compounds were characterized by their spectroscopic data. The antiproliferative activity of the compounds was evaluated in vitro via the MTT method in three tumor cell lines, including A-375 (human malignant melanoma cells), SPC-A1 (human lung adenocarcinoma) and NCI-H446 (small cell lung cancer). The results showed that the antiproliferative activity of all of the compounds on the NCI-H446 cell line did not increase compared to RA, however, most of the derivatives exhibited higher activity against the A375 and SPC-A1 cell lines as compared to RA. Importantly, the antiproliferative activities of compounds 5a and 5b were the highest among the compounds, with IC50 values <10 μM. Collectively, compounds 5a and 5b may act as potential anti-tumor agents in the future.

Synthesis and anticancer activity of novel fluorinated asiatic acid derivatives

A series of novel fluorinated Asiatic Acid (AA) derivatives were successfully synthesized, tested for their antiproliferative activity against HeLa and HT-29 cell lines, and their structure activity relationships were evaluated. The great majority of fluorinated derivatives showed stronger antiproliferative activity than AA in a concentration dependent manner. The most active compounds have a pentameric A-ring containing an α,β-unsaturated carbonyl group. The compounds with better cytotoxic activity were then evaluated against MCF-7, Jurkat, PC-3, A375, MIA PaCa-2 and BJ cell lines. Derivative 14 proved to be the most active compound among all tested derivatives and its mechanism of action was further investigated in HeLa cell line. The results showed that compound 14 induced cell cycle arrest in G0/G1 stage as a consequence of up-regulation of p21(cip1/waf1) and p27(kip1) and down-regulation of cyclin D3 and Cyclin E. Furthermore, compound 14 was found to induce caspase driven-apoptosis with activation of caspases-8 and caspase-3 and the cleavage of PARP. The cleavage of Bid into t-Bid, the up-regulation of Bax and the down-regulation of Bcl-2 were also observed after treatment of HeLa cells with compound 14. Taken together, these mechanistic studies revealed the involvement of extrinsic and intrinsic pathways in the apoptotic process induced by compound 14. Importantly, the antiproliferative activity of this compound on the non-tumor BJ human fibroblast cell line is weaker than in the tested cancer cell lines. The enhanced potency (between 45 and 90-fold more active than AA in a panel of cancer cell lines) and selectivity of this new AA derivative warrant further preclinical evaluation.

AA-PMe, a novel asiatic acid derivative, induces apoptosis and suppresses proliferation, migration, and invasion of gastric cancer cells

Asiatic acid (AA; 2α,3β,23-trihydroxyurs-12-ene-28-oic acid) is widely used for medicinal purposes in many Asian countries due to its various bioactivities. A series of AA derivatives has been synthesized in attempts to improve its therapeutic potencies. Herein we investigated the anti-tumor activities of N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-l-proline methyl ester (AA-PMe), a novel AA derivative. AA-PMe exhibited a stronger anti-cancer activity than its parent compound AA. AA-PMe inhibited the proliferation of SGC7901 and HGC27 human gastric cancer cells in a dose-dependent manner but had no significant toxicity in human gastric mucosa epithelial cells (GES-1). AA-PMe induced cell cycle arrest in G₀/G₁ phase and blocked G₁-S transition, which correlated well with marked decreases in levels of cyclin D1, cyclin-dependent kinase CKD4, and phosphorylated retinoblastoma protein, and increase in cyclin-dependent kinase inhibitor P15. Further, AA-PMe induced apoptosis of human gastric cancer cells by affecting Bcl-2, Bax, c-Myc, and caspase-3. Moreover, AA-PMe suppressed the migration and invasion of human gastric cancer cells (SGC7901 and HGC27) cells by downregulating the expression of MMP-2 and MMP-9. Overall, this study investigated the potential anti-cancer activities of AA-PMe including inducing apoptosis and suppressing proliferation, migration and invasion of gastric cancer cells, as well as the underlying mechanisms, suggesting that AA-PMe is a promising anti-cancer drug candidate in gastric cancer therapy.

Anti-glioma activity and the mechanism of cellular uptake of asiatic acid-loaded solid lipid nanoparticles

Asiatic acid (AA), a pentacyclic triterpene found in Centella Asiatica, has shown neuroprotective and anti-cancer activity against glioma. However, owing to its poor aqueous solubility, effective delivery and absorption across biological barriers, in particular the blood brain barrier (BBB), are challenging. Solid lipid nanoparticles (SLNs) have shown a promising potential as a drug delivery system to carry lipophilic drugs across the BBB, a major obstacle in brain cancer therapy. Nevertheless, limited information is available about the cytotoxic mechanisms of nano-lipidic carriers with AA on normal and glioma cells. This study assessed the anti-cancer efficacy of AA-loaded SLNs against glioblastoma and their cellular uptake mechanism in comparison with SVG P12 (human foetal glial) cells. SLNs were systematically investigated for three different solid lipids; glyceryl monostearate (MS), glyceryl distearate (DS) and glyceryl tristearate (TS). The non-drug containing MS-SLNs (E-MS-SLNs) did not show any apparent toxicity towards normal SVG P12 cells, whilst the AA-loaded MS-SLNs (AA-MS-SLNs) displayed a more favourable drug release profile and higher cytotoxicity towards U87 MG cells. Therefore, MS-SLNs were chosen for further in vitro studies. Cytotoxicity studies of SLNs (± AA) were performed using MTT assay where AA-SLNs showed significantly higher cytotoxicity towards U87 MG cells than SVG P12 normal cells, as confirmed by flow cell cytometry. Cellular uptake of SLNs also appeared to be preferentially facilitated by energy-dependent endocytosis as evidenced by fluorescence imaging and flow cell cytometry. Using the Annexin V-PI double staining technique, it was found that these AA-MS-SLNs displayed concentration-dependent apoptotic activity on glioma cells, which further confirms the potential of exploiting these AA-loaded MS-SLNs for brain cancer therapy.