Antitumor and antioxidant activity of Polyalthia longifolia stem bark ethanol extract

Four Togolese plant species exhibiting cytotoxicity and antitumor activities lightning polytherapy approach in cancer treatment

Background

Cancer is leading to premature deaths across the globe. Therapeutic approaches are still being developed to enhance the survival of cancer patients. In our previous study, extracts from four Togolese plants, namely, Cochlospermum planchonii (CP), Piliostigma thonningii (PT), Paullinia pinnata (PP), and Securidaca longipedunculata (SL), actually used in traditional medicine for cancer treatment, showed beneficial health effects against oxidative stress, inflammation, and angiogenesis.

Purpose

In the present study, we aimed to investigate the cytotoxicity and antitumor activities of these four plant extracts.

Material and methods

Breast, lung, cervical, and liver cancer cell lines were exposed to the extracts, and viability was assessed using the Sulforhodamine B method. P. pinnata and S. longipedunculata with significant cytotoxicity were selected for in vivo tests. The acute oral toxicity of these extracts was assessed using BALB/c mice. The antitumor activity was evaluated using the EAC tumor bearing mice model, wherein mice were orally treated with extracts at different concentrations for 14 days. The standard drug was cisplatin (3.5 mg/kg, i.p), single dose.

Results

Cytotoxicity tests revealed that SL, PP, and CP extracts have more than 50% cytotoxicity at 150 μg/mL. The acute oral toxicity of PP and SL at 2000 mg/kg did not show any toxic signs. At therapeutic doses of 100 mg/kg, 200 mg/kg and 400 mg/kg of PP and 40 mg/kg, 80 mg/kg, and 160 mg/kg of SL, extracts showed beneficial health effects by modulating several biological parameters. SL extract significantly reduced tumor volume (P < 0.001), cell viability, and normalized hematological parameters. SL also demonstrated a strong anti-inflammatory activity similar to the standard drug. The SL extract also revealed a significant increase of the life span of treated mice. PP extract reduced the tumor volume and significantly improved the values of endogenous antioxidants. Both PP and SL extracts also exerted significant anti-angiogenic potency.

Conclusion

The study indicated that polytherapy would be a panacea for the efficient use of medicinal plant extracts against cancer. This approach will make it possible to act simultaneously on several biological parameters. Molecular studies of both extracts targeting key cancer genes in several cancer cells are currently underway.

Phytochemicals from Polyalthia Species: Potential and Implication on Anti-Oxidant, Anti-Inflammatory, Anti-Cancer, and Chemoprevention Activities

Polyalthia belong to the Annonaceae family and are a type of evergreen tree distributed across many tropical and subtropical regions. Polyalthia species have been used long term as indigenous medicine to treat certain diseases, including fever, diabetes, infection, digestive disease, etc. Recent studies have demonstrated that not only crude extracts but also the isolated pure compounds exhibit various pharmacological activities, such as anti-oxidant, anti-microbial, anti-tumor, anti-cancer, etc. It is known that the initiation of cancer usually takes several years and is related to unhealthy lifestyle, as well as dietary and environmental factors, such as stress, toxins and smoking. In fact, natural or synthetic substances have been used as cancer chemoprevention to delay, impede, or even stop cancer growing. This review is an attempt to collect current available phytochemicals from Polyalthia species, which exhibit anti-cancer potentials for chemoprevention purposes, providing directions for further research on the interesting agents and possible clinical applications.

Process optimization for biosynthesis of mono and bimetallic alloy nanoparticle catalysts for degradation of dyes in individual and ternary mixture

Nanoparticle (NP) catalysts are widely used for removal of dyes for single use, but there is an acute need for developing catalysts with high efficiency and reusability for mixed dyes. Here we first optimized the process (reactant proportion, temperature, time, and pH) for biosynthesis of monometallic Ag, Au and bimetallic Au-Ag alloy NP catalysts using Polyalthia longifolia leaf extract. The biosynthesized NP catalysts were characterized by UV-vis, DLS, Zeta potential, TEM and EDX study while the probable biomolecules responsible for biosynthesis were identified by FTIR and GC-MS/MS analysis. The NPs are found to be mostly spherical in shape (size 5-20 nm) with prolonged stability. We evaluated their chemo-catalytic performance through degradation of dyes (methyl orange, methyl violet, methylene blue) in individual and ternary mixture in presence of NaBH4. The degradation percentage (80.06-96.59% within 5 min), degradation kinetics (k = 0.361-1.518 min-1), half-life (T50 = 0.457-1.920 min) and 80% degradation (T80 = 1.060-4.458 min) of dyes indicated highest catalytic activity of alloy in ternary mixture. Here we report a unique vacuum filtration system using alloy coated beads with excellent catalytic activity which could be reused thrice for removal of hazardous ternary mixed dyes with great promise for environmental remediation.

Polyalthia longifolia Extract Triggers ER Stress in Prostate Cancer Cells Concomitant with Induction of Apoptosis: Insights from In Vitro and In Vivo Studies

Plant-based therapies are being explored to prevent or treat several cancer types. The antioxidant properties of Polyalthia longifolia plant are well established. In our previous work, we demonstrated the presence of cytotoxic compounds in the methanol extract of Polyalthia longifolia (MEP) with potent activity against human leukemia cells. In the present study, we evaluated the efficacy of MEP against prostate cancer (PCa) and established the molecular basis of its effect in in vitro and in vivo models. We observed that MEP treatment resulted in a significant decrease in the growth and viability of PCa cells, associated with arrest in the G1/S phase of the cell cycle. Apoptosis was confirmed as the primary mode of MEP-induced cell death through activation of the intrinsic apoptotic machinery. Proteomic and biochemical studies identified BiP as an important target of MEP with the activation of the ER stress pathway, as a potential mechanism driving MEP-induced apoptosis. The extract exhibited strong efficacy in the PCa xenograft mouse model with significant inhibition of tumor growth and reduced tumor burden. Taken together, our findings indicate that MEP-induced apoptosis in PCa cells concomitant with the activation of the ER stress pathways results in the inhibition of tumor growth, in vitro and in vivo. Our studies provide initial evidence of the efficacy of MEP against PCa and advocate for in-depth studies in other preclinical models for its possible use in clinical settings.

Flavonoids from Polyalthia longifolia prevents advanced glycation end products formation and protein oxidation aligned with fructose-induced protein glycation

Advanced glycation end products (AGEs) are reactive chemical entities formed by non-enzymatic reaction between reducing sugars and amino group of proteins. Enhanced accumulation of AGEs and associated protein oxidation contribute to pathogenesis of diabetes-associated complications. Here, we evaluated the inhibitory activity of flavonoid compounds isolated from the leaves of Polyalthia longifolia on formation of AGEs and protein oxidation. Antiglycation activity was determined by measuring the formation of AGE fluorescence intensity, Nε-(carboxymethyl) lysine, and level of fructosamine. Protein oxidation was examined using levels of protein carbonyls and thiol group. Compounds significantly (p < 0.001) restricted the formation of fluorescent AGEs in fructose- BSA and methylglyoxal-BSA systems. Furthermore, there was a decrease in levels of fructosamine and protein carbonyls, and elevation in level of thiol group in fructose-BSA in presence of flavonoids. In summary, flavonoids from Polyalthia longifolia inhibit fructose-mediated protein glycation and oxidation, and can be potential agent for preventing AGE-mediated diabetic complications.

Synthesis and evaluation of selected 1,3,4-oxadiazole derivatives for in vitro cytotoxicity and in vivo anti-tumor activity

The oxadiazole moiety is known for its anticancer activity through its antiangiogenic and mitostatic potential. Taking this as a cue, the present study was designed to investigate the anti-cancer potential of selected oxadiazole derivatives. Twelve 1,3,4-oxadiazole derivatives (AMK OX-1 to AMK OX-12) were synthesized and were tested for IC50 values through brine shrimp lethality assay and MTT assay on HeLa and A549 cell lines. Four compounds, AMK OX-8, 9, 11 and 12 showed potential cytotoxicity activity with low IC50 value. These compounds produced considerable cytotoxic effect on Hep-2 and A549 cancer cell lines. However, they were found to be comparatively safer to normal cell lines, viz., V-79 cell lines than to the tested cancer cell lines, such as HeLa, A 549, and Hep2 cell lines. The mechanism of cytotoxicity was evaluated through nuclear staining and DNA ladder assay. Although DNA ladder assay showed DNA fragmentation (apoptotic phenomenon) in Hep-2 cells treated with only AMK OX-12, the staining procedures using acridine orange, ethidium bromide and propidium iodide showed apoptotic bodies in cells treated with AMK OX-8, 9 and 12 also. In JCI staining on isolated mitochondria of Hep2 cells, AMK OX-8, 9-11 and 12 displayed increasing fluorescence intensity with time which confirmed involvement of mitochondrial pathway and intrinsic pathway of apoptosis. All four compounds were found to be safe in acute oral toxicity study in Swiss albino mice. These derivatives were effective in reducing tumor size and weight in the in vivo DLA-induced solid tumor model. They were found to be significantly effective in reducing tumor volume and tumor weight.

Assessment of the in vitro cytotoxicity and in vivo anti-tumor activity of the alcoholic stem bark extract/fractions of Mimusops elengi Linn

Various parts of Mimusops elengi Linn. (Sapotaceae) have been used widely in traditional Indian medicine for the treatment of pain, inflammation and wounds. The study was conducted to explore the use of stem bark of M. elengi on pharmacological grounds and to evaluate the scientific basis of cytotoxic and anti-tumor activity. Extract/fractions were prepared and in vitro cytotoxicity was assessed using SRB assay. Most effective fractions were subjected to fluorescence microscopy based acridine orange/ethidium bromide (AO/EB) and Hoechst 33342 staining to determine apoptosis induction and DNA fragmentation assay. Comet and micronuclei assay were performed to assess genotoxicity. Cell cycle analysis was also performed. In vivo anti-tumor potential was evaluated by Ehrlich ascites carcinoma (EAC) model in mice. The alcoholic stem bark extract of M. elengi along with four fractions showed potential in vitro cytotoxicity in SRB assay. Of these, dichloromethane and ethyl acetate fractions were selected for further studies. The fractions revealed apoptosis inducing potential in AO/EB and Hoechst 33342 staining, which was further confirmed by DNA fragmentation assay. Genotoxic potential was revealed by comet and micronuclei assay. Fractions also exhibited specific cell cycle inhibition in G0/G1 phase. In EAC model, ethyl acetate fraction along with the standard (cisplatin) effectively reduced the increase in body weight compared to control and improved mean survival time. Both fractions were able to restore the altered hematological and biochemical parameters. Hence, M. elengi stem bark may be a possible therapeutic candidate having cytotoxic and anti-tumor potential.

Evaluation of Ceiba pentandra (L.) Gaertner bark extracts for in vitro cytotoxicity on cancer cells and in vivo antitumor activity in solid and liquid tumor models

The stem bark of Ceiba pentandra (L.) Gaertner is claimed to be useful in the treatment of tumors in the southern part of India. This plant possesses a number of sesquiterpenoids and isoflavones which are known for their anticancer properties. The present study was designed to scientifically evaluate the cytotoxic potential of bark extracts in in vitro on Ehrlich ascites carcinoma (EAC), MCF-7 and B16F10 cells and in vivo in EAC (Liquid tumor) model and Dalton's lymphoma ascites (DLA or solid tumor) model. The bark was powdered and extracted successively with solvents viz., petroleum ether (PE), benzene, chloroform, acetone (AC), and ethyl alcohol in the sequential order of polarity. Cytotoxicity of dried extracts was screened on EAC cells by trypan blue assay. Three potent extracts namely petroleum ether, acetone, and ethanol were screened for their cytotoxicity on MCF-7 and B16F10 cells by MTT assay and nucleomorphological alteration by propidium iodide staining. Safe doses of these extracts were evaluated by acute toxicity study in mice. Extracts were found to be safe up to 300 mg/kg in acute toxicity study. Dosage of 1/10th and 1/20th of safe dose i.e., 15 and 30 mg/kg were selected for in vivo study. In the EAC model, both doses of the extracts showed a significant (P < 0.05) improvement in mean survival time and a maximum decline in tumor induced increase in body weight (an indirect measure of tumor weight) by the PE and AC treatment at 15 mg/kg compared to control. In the DLA-model, all extracts at both tested dose levels showed >50 % reduction in tumor weight and a significant reduction (P < 0.05) in tumor volume on the 30th day compared to control. It can be concluded that these extracts possess cytotoxic and antitumor activity.

A clerodane diterpene inhibit adipogenesis by cell cycle arrest and ameliorate obesity in C57BL/6 mice

A clerodane diterpene, 16α-Hydroxycleroda-3, 13 (14) Z-dien-15, 16-olide (compound 1) isolated from Polyalthia longifolia had previously been reported as a new structural class of HMG-CoA reductase inhibitor apart from statins. Statins are known to be anti-adipogenic in nature. The distant structural similarity between compound 1 and lovastatin (polyketide class of compound) prompted us to investigate effects of diterpene compound 1 on adipogenesis and thereby obesity. High content microscopy proved diterpene compound 1 exhibits better anti-adipogenic activity and less toxicity in differentiating adipocytes. Moreover, it reduced expression levels of PPARγ, C/EBPα and GLUT4 during differentiation in a time and concentration dependent manner. Diterpene compound 1 during early differentiation reduced MDI induced-Akt/mTOR phosphorylation and expression of cell cycle proteins, and thereby halted mitotic clonal expansion, the decisive factor in early adipogenesis. Further, its anti-adipogenic activity was validated in murine mesenchymal cell-line C3H10T1/2 and human mesenchymal stem cell models of adipogenic differentiation. When compound 1 was administered along with HFD, for another 8 weeks in 2 month HFD fed overweight mice (with BMI > 30 and impaired glucose tolerance), it attenuated weight gain and epididymal fat accumulation. It improved body glucose tolerance, reduced HFD induced increase in total cholesterol and leptin/adiponectin ratio. All these effects were comparable with standard anti-obesity drug Orlistat with added edge of potently decreasing circulating triglyceride levels comparable with normal chow fed group. Histological analysis shows that compound 1 inhibit adipocyte hypertrophy and decreased steatosis in hepatocytes. Both in vivo and in vitro results demonstrate a potential value of compound 1 as a novel anti-adipogenic and anti-obesity agent.

Leucas aspera inhibits the Dalton's ascitic lymphoma in Swiss albino mice: A preliminary study exploring possible mechanism of action

Background:

North East India is a rich source of medicinal plants and a number of plant extracts are used by tribal peoples living in this area for various disorders. L.aspera is such a plant, traditionally used as an antitumor agent.

Aim:

In the present study, aerial parts of L.aspera were investigated for antitumor activity in Dalton's lymphoma (DAL) bearing mice. The ability of plant extract in free radical scavenging, neoangiogenesis inhibition and macrophage stimulation were also checked.

Materials and Methods:

Based on the preliminary in vitro cytotoxicity studies ethyl acetate fraction of L.aspera (EALA) was selected for the detailed study. DAL ascites tumor model was performed to check the antitumor activity of EALA (200 and 400mg/kg of body weight). Hematological and histopathological parameters were estimated. Antioxidant levels, neoangiogenesis and peritoneal macrophage count were also determined.

Results:

In vitro MTT and Trypan blue assay results showed the cytotoxic effect of EALA in DAL cells lines. EALA treatment resulted in significant decrease in ascites tumor volume and viable cell count. Hematological and liver antioxidant parameters were normalised by EALA treatment. It was also found that EALA treatment inhibits neovascularisation and produce macrophage stimulation in treated mice.

Conclusion:

The results showed that EALA is a promising anticancer agent and its activity is comparable to the standard drug 5-Flouro uracil (5-FU).

In vitro and in vivo evaluation of the efficacy of nanoformulation of siRNA as an adjuvant to improve the anticancer potential of cisplatin

With the advent of advanced tools in molecular biology, understanding on cancer etiology has improved. siRNA can be considered as an effective tool in cancer therapy through silencing overexpressed genes responsible for cell proliferation or preventing apoptosis. However, some contentious issues such as stability and delivery of siRNA are to be resolved. Bcl-2, an anti-apoptotic gene, is overexpressed in a wide variety of cancers and responsible for drug resistance tumors. In our earlier studies, we developed a nanoformulation of siRNA targeting the Bcl-2 and achieved successful delivery in vitro and in vivo. To extend the scope of the study further, in the present work, we studied the role of nanoformulation of siRNA as adjuvant in chemotherapy with cisplatin. Dose dependant nephrotoxicity is a serious concern apart from other adverse effects of cisplatin. The IC(50) value for cisplatin was decreased from 9.83 μmol/l to 7.43 μmol/l in HeLa cells and from 8.54 μmol/l to 6.68 μmol/l in HEp-2 cells, when it was given with siRNA nanoformulation. Cisplatin at the dose of 1.7 mg/kg in combination with siRNA nanoformulation was effective in improving the lifespan of tumor bearing mice with significant decrease in nephrotoxicity.