Streblus asper Lour. (Shakhotaka): A Review of its Chemical, Pharmacological and Ethnomedicinal Properties

Benzo[b]naphtho[2,1-d]furans and 2-Phenylnaphthalenes from Streblus usambarensis

Three new benzo[b]naphtho[2,1-d]furans, usambarins A-C (1-3), five new 2-phenylnaphthalenes, usambarins D-H (4-8), a new flavan (9), and a new phenyl-1-benzoxepin (10) as well as two known compounds (11 and 12) were isolated from the extract of the stem and roots of Streblus usambarensis (Moraceae). The structures were deduced using NMR spectroscopic and mass spectrometric analyses, and those of compounds 1 and 4 were confirmed by X-ray crystallography. Usambarin D (4) demonstrated moderate antibacterial activity (MIC 9.0 μM) against Bacillus subtilis, while none of the tested compounds were effective against Escherichia coli.

The potency of herbal extracts and its green synthesized nanoparticle formulation as antibacterial agents against Streptococcus mutans associated biofilms

This study aims to determine the effects of the extracts of Streblus asper, Cymbopogon citratus, Syzygium aromaticum and its formulation of green synthesized silver nanoparticle (AgNPs) on Streptococcus mutans growth and biofilm formation. The ethanolic extracts of S. asper, C. citratus, S. aromaticum, and a mix of the three herbs demonstrated antibacterial activity against S. mutans isolates by reducing bacterial biofilm formation and decreasing bacterial cell surface hydrophobicity. The formulated AgNPs from the ethanolic extracts could enhance the antibacterial activities of the plant extracts. Molecular docking found the best interaction between luteolin isolated from C. citratus and glucosyltransferase protein (GtfB), assuming the promising anti-biofilm activity. The scanning electron microscopy revealed morphological changes in the biofilm structure and a significant decrease in the biofilm area of the AgNPs treated. The study suggested that the extracts and its application could be used as natural alternative agents with multi-action against S. mutans infections.

Streblus asper attenuates alloxan-induced diabetes in rats and demonstrates antioxidant and cytotoxic effects

CONTEXT

Streblus asper Lour. (Moraceae) is used for the treatment of different ailments, including diabetes, and requires scientific validation.

OBJECTIVE

The study evaluates antidiabetic effects, antioxidant potential, and cytotoxicity of leaf and bark extracts of S. asper.

MATERIALS AND METHODS

Antidiabetic effects were assessed by inducing diabetes in Wistar albino rats (n = 5, six groups included 30 rats) by injecting alloxan [0.25 mg/kg body weight (bw)] intraperitoneally, and efficacy of methanol extracts of leaf and bark, and aqueous extract of leaves were evaluated by oral administration of 300 mg/kg bw of extracts for 3 weeks. Glibenclamide (Dibenol™) was used as a control (10 mg/kg bw). Antioxidant properties were examined by DPPH free radical scavenging activity, and cytotoxicity was investigated using a brine shrimp lethality assay.

RESULTS

Methanol extracts of leaves and bark, and the aqueous extract of leaves of S. asper, caused significant reductions in blood glucose levels in diabetic rats of 36.83, 70.33, and 52.71%, respectively, after 21 days of treatment. IC₅₀ values in DPPH radical scavenging assessment for those extracts were 58.92, 88.54, and 111.36 µg/mL, respectively. LC₅₀ values for brine shrimp lethality for the extracts were 173.80, 32.36, and 3235.9 µg/mL, respectively.

DISCUSSION AND CONCLUSIONS

The methanol bark extract of S. asper showed significant antidiabetic activity. This study will significantly contribute to establishing the plant as an alternative medicinal resource for rural populations of Bangladesh and provides an opportunity for further research to identify the primary active compound(s) and establish new drug candidates.

Factors Influencing the Natural Forest Regeneration at Khadimnagar National Park, Bangladesh

Natural regeneration is an indicator of a healthy forest, hence, understanding the influence of site factors on natural regeneration is a significant concern for ecologists. This work aimed to assess the impact of site factors on natural tree regeneration at Khadimnagar National Park (KNP). Biotic factors (tree density, tree species richness, and basal area), physical factors (elevation, canopy openness), and soil properties (bulk density, moisture content, soil pH, organic matter, sand, silt, and clay) data were investigated from 71 sample plots to examine their effects on natural regeneration density and richness in KNP. Stepwise multiple linear regression analysis was done to predict both regeneration density and regeneration richness. The results showed that soil pH (p<0.001), canopy openness (p<0.001), tree species richness (p<0.01), and bulk density (p<0.01) had a significant effect on regeneration density, explaining 42% of the total variation. Regeneration richness was driven by four factors: tree species richness (p<0.01), soil pH (p<0.001), elevation (p<0.01), and canopy openness (p<0.01) with a model that explained 60% of the total variation. This study observed that soil pH, tree species richness, and canopy openness are the main controlling factors that influenced both the density and richness of regenerating species in KNP. Therefore, these findings have implications for natural resource management, especially in selecting suitable silvicultural systems in a tropical forest under protected area management where enhanced tree cover and conservation of biodiversity are needed.

Effect of Streblus asper Leaf Extract on Scopolamine-Induced Memory Deficits in Zebrafish: The Model of Alzheimer's Disease

Streblus asper (SA) is well known as a folk medicinal plant in Asian countries. The effect of SA extract on preventing memory impairment in zebrafish induced by scopolamine was investigated. Male zebrafish, Danio rerio, were divided into 6 groups including the control, scopolamine 200 μM (SCO), scopolamine plus rivastigmine 1.5 mg/kg (RV + SCO), and scopolamine plus SA extract at doses of 200, 400, and 800 mg/kg (SA200 + SCO, S400 + SCO, and SA800 + SCO), respectively. Spatial memory was evaluated by the colour-biased appetite conditioning T-maze test, while fear memory was measured by the inhibitory avoidance test. In the spatial memory test, results showed that the RV + SCO group had the best time spent ratio in the T-maze, followed by SA800 + SCO, SA400 + SCO, SA200 + SCO, control, and SCO group, respectively, but with no statistical significance. For the fear memory test, zebrafish that received SA at doses of 200, 400, and 800 mg/kg had significantly increased latency time as 21.75 ± 4.59, 23.75 ± 13.01, and 18.20 ± 18.84 min, respectively, when compared to the SCO group (9.80 ± 10.45 min). These results suggested that SA extract attenuated memory impairment in an inhibitory avoidance test related to fear memory. Our findings can be useful for further research to develop SA extract as a health product to ameliorate the symptoms of Alzheimer's disease.

Cardiac glycosides from the roots of Streblus asper Lour. and their apoptosis-inducing activities in A549 cells

Phytochemical investigation of the roots of Streblus asper Lour. resulted in the isolation of six previously undescribed cardiac glycosides, designated 2'-de-O-methylstrebloside (1), cannogenol-3α-O-β-D-gluopyranosyl-(1 → 4)-6-deoxy -2,3-dimethoxyl-β-D-fucopyranoside (2), periplogenin-3-O-α-L-rhamnopyranosyl -(1 → 4)-6-deoxy-β-D-allopyranoside (3), 5-de-O-hydroxylstrebloside (4), 5βH-16β-hydroxylkamaloside (5), and 17S, 21R-21-hydroxylstrebloside (6), and three known analogues (7-9). The structures were elucidated using NMR spectroscopic techniques, mass spectrometry, and comparison of the spectroscopic data with previously reported data. Compound 6 is a novel C-21 hydroxyl cardiac glycoside, its absolute configuration was established from the analysis of computational ECD calculations and NMR spectroscopic data. The effects of the cardiac glycosides on apoptosis and cytotoxicity were examined in human A549 lung cancer cells. All the compounds showed remarkable inhibitory activities, with IC₅₀ values in the range of 0.01-6.08 μM. Furthermore, compound 3 was able to significantly inhibit A549 cell growth proliferation via the induction of apoptosis, due to the activation of caspases-3, -8 and -9 in A549 cells, as revealed by Western blot analysis.

Antilipoxygenase and Anti-Inflammatory Activities of Streblus asper Leaf Extract on Xylene-Induced Ear Edema in Mice

Streblus asper (SA) belonging to the Moraceae family is well known as a folk medicinal plant in Asian countries. This study aimed to investigate the antilipoxygenase activity and the anti-inflammatory effects of the SA leaf extract. An in vitro antilipoxygenase study was performed using a lipoxygenase assay, and the oxidation of linoleic acid into 13-hydroperoxy linoleic acid (HPODE) was detected with a UV spectrophotometer at a wavelength of 234 nm. In the animal study, twenty-five male ICR mice were induced as ear edema by topical xylene, and the ear thickness of the mice was measured. The lipoxygenase assay results showed that the IC50 values of diclofenac sodium and SA were 0.0015 and 37.96 μg/mL, respectively. In the animal study, mice that received diclofenac sodium exhibited significantly reduced ear edema induced by xylene from 30 min onward, while mice that received 250 mg/kg and 500 mg/kg SA exhibited significantly reduced ear edema compared with the control group 45 min after induction with xylene. These results suggested that the SA leaf extract had anti-inflammatory activity. However, further studies are required to evaluate these effects and the additional potential of the plant that might be beneficial for the development of pharmaceutical products that prevent and treat inflammation.

Potential Thai medicinal plants for neurodegenerative diseases: A review focusing on the anti-glutamate toxicity effect

Neurodegenerative diseases (NDD) are a range of debilitating conditions of the brain involving progressive loss of neurons, many of which are still currently incurable despite enormous efforts on drug discovery and development in the past decade. As NDD is closely linked to old age, the rapid worldwide growth in the aging population contributes to an increasing number of people with one of these incurable diseases and therefore it is considered a significant global health issue. There is an urgent need for novel effective treatments for NDD, and many new research strategies are centered on traditional medicine as an alternative or complementary solution. Several previous findings have suggested that glutamate toxicity drives neurodegeneration in many NDD, and the medicinal plants with anti-glutamate toxicity properties can be potentially used for their treatment. In order to obtain data relating to natural products against glutamate toxicity, six candidate plant species of Thailand were identified. Studies utilizing these herbs were searched for using the herb name (Latin and common names) along with the term "glutamate" in the following databases across all available years: PubMed, Scopus, and Google Scholar. This review emphasizes the importance of glutamate toxicity in NDD and summarizes individual plants and their active constituents with the mechanism of action against glutamate toxicity-mediated neuronal cell death that could be a promising resource for future NDD therapy.

TAXONOMY CLASSIFICATION BY EVISE

Alzheimer's disease, Neurodegenerative diseases, Cell culture, Molecular Biology, Traditional herbal medicine, Oxidative stress, Glutamate neurotransmitter.

Medicinal plants with acetylcholinesterase inhibitory activity

Alzheimer's disease, a progressive neurodegenerative disease, is characterised by hypofunction of acetylcholine (ACh) neurotransmitter in the distinct region of brain. Acetylcholinesterase (AChE) is an enzyme that metabolises the ACh at synaptic cleft resulting in Alzheimer's disease. Medicinal plants have been used to treat numerous ailments and improve human health from ancient time. A traditional system of medicine is long recognised for its effective management of neurological disorders. The present review confers the scope of some common medicinal plants with a special focus on AChE-mediated central nervous system complications especially Alzheimer's disease. Literature suggests that medicinal plants reduce neuronal dysfunctions by reducing AChE activity in different brain regions. In some instances, activation of AChE activity by medicinal plants also showed therapeutic potential. In conclusion, medicinal plants have a wide scope and possess therapeutic potential to efficiently manage neurological disorders associated with AChE dysregulation.

Acid-base fractions separated from Streblus asper leaf ethanolic extract exhibited antibacterial, antioxidant, anti-acetylcholinesterase, and neuroprotective activities

BACKGROUND

Streblus asper is a well-known plant native to Southeast Asia. Different parts of the plant have been traditionally used for various medicinal purposes. However, there is very little scientific evidence reporting its therapeutic benefits for potential treatment of Alzheimer's disease (AD). The study aimed to evaluate antibacterial, antioxidant, acetylcholinesterase (AChE) inhibition, and neuroprotective properties of S. asper leaf extracts with the primary objective of enhancing therapeutic applications and facilitating activity-guided isolation of the active chemical constituents.

METHODS

The leaves of S. asper were extracted in ethanol and subsequently fractionated into neutral, acid and base fractions. The phytochemical constituents of each fraction were analyzed using GC-MS. The antibacterial activity was evaluated using a broth microdilution method. The antioxidant activity was determined using DPPH and ABTS radical scavenging assays. The neuroprotective activity against glutamate-induced toxicity was tested on hippocampal neuronal HT22 cell line by evaluating the cell viability using MTT assay. The AChE inhibitory activity was screened by thin-layer chromatography (TLC) bioautographic method.

RESULTS

The partition of the S. asper ethanolic leaf extract yielded the highest mass of phytochemical constitutions in the neutral fraction and the lowest in the basic fraction. Amongst the three fractions, the acidic fraction showed the strongest antibacterial activity against gram-positive bacteria. The antioxidant activities of three fractions were found in the order of acidic > basic > neutral, whereas the decreasing order of neuroprotective activity was neutral > basic > acidic. TLC bioautography revealed one component in the neutral fraction exhibited anti-AChE activity. While in the acid fraction, two components showed inhibitory activity against AChE. GC-MS analysis of three fractions showed the presence of major phytochemical constituents including terpenoids, steroids, phenolics, fatty acids, and lipidic plant hormone.

CONCLUSIONS

Our findings have demonstrated the therapeutic potential of three fractions extracted from S. asper leaves as a promising natural source for neuroprotective agents with additional actions of antibacterials and antioxidants, along with AChE inhibitors that will benefit in the development of new natural compounds in therapies against AD.

In Vivo Anti-diarrheal Activity of Methanolic Extract of Streblus asper Leaves Stimulating the Na+/K+-ATPase in Swiss Albino Rats

Streblus asper Lour., traditionally used for anti-diarrheal effects as like dysentery and diarrhea. The present study aims to prove the anti-diarrheal activities of methanolic extract of leaves of S. asper in animal models. The anti-diarrheal activity was evaluated using castor oil-induced diarrhea and magnesium sulphate-induced diarrhea models whereas anti-motility activities were investigated using gastrointestinal transit test examined in animal models. In castor oil-induced diarrhea model, methanolic extract of S. asper (MESA) at the doses of 100, 200, and 400 mg/kg produced statistically significant (P < 0.001) decreased the number of diarrheal feces of rats against castor oil-induced diarrhea as well as magnesium sulphate-induced diarrhea model also showed the same manner. In gastrointestinal transit test, delayed gastric emptying time decreased significantly (P < 0.001), the propulsion of charcoal meal in the gastrointestinal tract which also showed a dose-dependent manner in rats. The recent study indicates that MESA possesses anti-diarrheal property. The findings represent a rational explanation for its use in traditional medicine for the management of diarrhea management.

Ethnobotany of dioecious species: Traditional knowledge on dioecious plants in India

ETHNOPHARMACOLOGICAL RELEVANCE

More than 15,000 angiosperm species are dioecious, i.e., having distinct male and female individual plants. The allocation of resources between male and female plants is different, and also variation in secondary metabolites and sex-biased herbivory is reported among dioecious plants. However, little is known about the ethnobotany of dioecious species and whether preferences exist for a specific gender, e.g., in food, medicine or timber.

AIM OF THE STUDY

The aim of this study was: 1) to study whether Indian folk healers have preference for plant genders, and to document their knowledge and use of dioecious species; 2) to understand the concept of plant gender in Indian systems of medicine and folk medicine, and whether Ayurvedic literature includes any references to gender preference.

MATERIALS AND METHODS

Lists of dioecious plants used in Indian systems of medicine and folk medicine were compiled. Ethnobotanical data was collected on perceptions and awareness of dioecious plants, and preferences of use for specific genders of dioecious species using semi-structured interviews with folk healers in Tamil Nadu, India. In addition, twenty Ayurvedic doctors were interviewed to gain insight into the concept of plant gender in Ayurveda.

RESULTS

Indian systems of medicine contain 5-7% dioecious species, and this estimate is congruent with the number of dioecious species in flowering plants in general. Informants recognized the phenomenon of dioecy in 31 out of 40 species, and reported gender preferences for 13 species with respect to uses as timber, food and medicine. Among informants different plant traits such as plant size, fruit size, and visibility of fruits determines the perception of a plant being a male or female. Ayurvedic classical literature provides no straightforward evidence on gender preferences in preparation of medicines or treatment of illness, however it contains details about reproductive morphology and sexual differentiation of plants.

CONCLUSIONS

A knowledge gap exists in ethnobotanical and ethnopharmacological literature on traditional knowledge of dioecious plants. From this explorative study it is evident that people have traditional knowledge on plant gender and preferential usages towards one gender. Based on this, we propose that researchers conducting ethnobotanical and ethnopharmacological studies should consider documenting traditional knowledge on sexual systems of plants, and test the existence of gender specific usages in their conceptual framework and hypothesis testing. Incorporating such concepts could provide new dimensions of scientific knowledge with potential implications to conservation biology, chemical ecology, ethnoecology and drug discovery.

Chemical Composition and Cytotoxic Activity of Methanol Extract and its Fractions of Streblus asper Leaves on Human Cancer Cell Lines

Background:

Streblus asper, family Moraceae is well-known important medicinal plant used in the Indian system of medicine. In Ayurveda, stem bark of S. asper is recommended against elephantiasis for which there is still no any other effective medicine in the modern system of medicine.

Objectives:

In the present work, methanol extract (SAM) and its fractions of S. asper leave tested for in vitro anticancer activity against cancer cell lines (MCF-7, A-549, Hep-G2, and K-562) which claims its folklore importance in cancer and gas chromatography-mass spectrometry identification of extracts was also performed.

Materials and Methods:

Shade dried plant material was extracted with methanol and fractionated sequentially with hexane, chloroform, and butanol.

Results:

All tested extracts found highly effective against human lung cancer cell line (A-549) with IC₅₀ <10 μg/mL. On Hep-G2 cancer cell line, only chloroform fraction are highly active with IC₅₀ <10 μg/mL. Methanol and hexane fraction showed potent anticancer activity on K-562 cancer cell line with IC₅₀ <10 μg/mL.

Conclusion:

Qualitative phytochemical analysis confirmed the presence of fatty acids, phytosterol, triterpenoids, polyol, sugar acid, aldehyde, diterpene, terpene, carboxylic compounds, acid and sugar in S. asper leaves extract. Topmost abundant compounds in SAM are α-D-glucopyranoside (10.60%), glycerol (7.96%), myo-inositol (4.90%), and butanedioic acid (3.30%). Hexane consists of the higher amount of hexadecanoic acid (18.07%), octadecanoic acid (7.39%), β-sitosterol (4.50%), and α-D-glucopyranoside (4.03%). Higher component in chloroform extract is lupenyl acetate (11.25%).

SUMMARY

All extracts of Streblus asper found potential anticancer activity against lung cancer cell line (A-549)

Chloroform fraction is highly active on hepatoma cancer cell line (Hep-G2) whereas methanolic, and hexane fractions have highly cytotoxic potency against leukemia cancer cell line (K-562)

Methanolic extract of S. asper is rich source of glycosides, fatty acids, and phytosterol

In Gas chromatography-mass spectrometry evaluation of S. asper β-stigmasterol, β-sitosterol, lycopene, and lupeol identified as an anticancer agent from previously reported literature.

Abbreviations used: SRB: Sulforhodamine B assay; SAM: Methanol extract; SAH: Hexane extract; SAC: Chloroform extract.

Three new cardiac glycosides obtained from the roots ofStreblus asperLour. and their cytotoxic and melanogenesis-inhibitory activities

Three new cardiac glycosides strophanthidin-3-O-α-l-rhamnopyranosyl-(1→4)-6-deoxy-β-d-allopyranoside (1), 5βH-16β-acetylkamaloside (2), and mansonin-19-carboxylic acid (3) along with seven known steroids including five cardiac glycosides were isolated from the methanol extracts of Streblus asper Lour. roots. The structures of these compounds were established by spectroscopic analyses. The cytotoxicities of crude extracts and all the isolated compounds were evaluated against four human cancer cell lines (HL60, A549, AZ521, and SKBR3). Furthermore, the selective index (SI) of each compound was measured by the ratio of cytotoxic effect on a normal cell line (WI38) to the cytotoxic effect on cancer cell line (A549). The results suggested that cardiac glycosides (2, 4, and 6–8) exhibited significant cytotoxicities with IC₅₀ values from 0.01 to 3.77 μM as well as high selective index for WI38/A549 (SI 1.50–24.26), and they displayed superior selectivities when compared with the reference cisplatin (SI 1.09). Preliminary structure–activity relationships (SARs) were also discussed regarding the type of C-10 group in the cardiac glycosides being a crucial factor in determining the cytotoxic activities and regarding the sugar moieties having much less of an active role than the type of C-10 group. In addition, the melanogenesis-inhibitory abilities of these compounds were also evaluated. Cardiac glycosides (3 and 6–8) displayed moderate inhibition effects on melanogenesis with melanin content (MC) of 26.22–74.90% at a concentration of 100 μM, thus showing high cell viability (CV: 77.94–111.70%) compared with that of the reference arbutin (MC: 82.50% and CV: 107.60%). Furthermore, western blot analysis of melanogenesis-related proteins suggested that 3 could inhibit melanogenesis by suppressing the protein expressions of TRP-2 and tyrosinase.

The cardiac glycosides isolated from the methanol extracts of Streblus asper Lour. roots indicated potent cytotoxicities and high selective index, and the mechanism of melanogenesis-inhibition was explored.

Ethanolic extract of Streblus asper leaves protects against glutamate-induced toxicity in HT22 hippocampal neuronal cells and extends lifespan of Caenorhabditis elegans

Background

Although such local herb as Streblus asper (family Moraceae) has long been recognized for traditional folk medicines and important ingredient of traditional longevity formula, its anti-neurodegeneration or anti-aging activity is little known. This study aimed to investigate the neuroprotective effect of S. asper leaf extracts (SA-EE) against toxicity of glutamate-mediated oxidative stress, a crucial factor contributing to the neuronal loss in age-associated neurodegenerative diseases and the underlying mechanism as well as to evaluate its longevity effect.

Methods

Using mouse hippocampal HT22 as a model for glutamate oxidative toxicity, we carried out MTT and LDH assays including Annexin V-FITC/propidium iodide staining to determine the SA-EE effect against glutamate-induced cell death. Antioxidant activities of SA-EE were evaluated using the radical scavenging and DCFH-DA assays. To elucidate the underlying mechanisms, SA-EE treated cells were analyzed for the expressions of mRNA and proteins interested by immunofluorescent staining, western blot analysis and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) techniques. The longevity effect of SA-EE was examined on C. elegans by lifespan assay.

Results

We demonstrate that a concentration-dependent reduction of glutamate-induced cytotoxicity was significant after SA-EE treatment as measured by MTT and LDH assays. Annexin V-FITC/propidium iodide and immunofluorescent staining showed that co-treatment of glutamate with SA-EE significantly reduced apoptotic-inducing factor (AIF)-dependent apoptotic cell death. DCFH-DA assay revealed that this extract was capable of dose dependently attenuating the ROS caused by glutamate. Western blot analysis and qRT-PCR showed that nuclear factor erythroid 2-related factor 2 (Nrf2) protein levels in the nucleus, as well as mRNA levels of antioxidant-related genes under Nrf2 regulation were significantly increased by SA-EE. Furthermore, this extract was capable of extending the lifespan of C. elegans.

Conclusions

SA-EE possesses both longevity effects and neuroprotective activity against glutamate-induced cell death, supporting its therapeutic potential for the treatment of age-associated neurodegenerative diseases.

(+)-Strebloside-Induced Cytotoxicity in Ovarian Cancer Cells Is Mediated through Cardiac Glycoside Signaling Networks

(+)-Strebloside, a cardiac glycoside isolated from the stem bark of Streblus asper collected in Vietnam, has shown some potential for further investigation as an antineoplastic agent. A mechanistic study using an in vitro assay and molecular docking analysis indicated that (+)-strebloside binds and inhibits Na+/K+-ATPase in a similar manner to digitoxin. Inhibition of growth of different high-grade serous ovarian cancer cells including OVCAR3, OVSAHO, Kuramochi, OVCAR4, OVCAR5, and OVCAR8 resulted from treatment with (+)-strebloside. Furthermore, this compound blocked cell cycle progression at the G2 phase and induced PARP cleavage, indicating apoptosis activation in OVCAR3 cells. (+)-Strebloside potently inhibited mutant p53 expression through the induction of ERK pathways and inhibited NF-κB activity in human ovarian cancer cells. However, in spite of its antitumor potential, the overall biological activity of (+)-strebloside must be regarded as being typical of better-known cardiac glycosides such as digoxin and ouabain. Further chemical alteration of cardiac glycosides might help to reduce negative side effects while increasing cancer cell cytotoxicity.

Structural Characterization and Assessment of the Cytotoxicity of 2,3-Dihydro-1H-indene Derivatives and Coumarin Glucosides from the Bark of Streblus indicus

A pair of enantiomers and a pair of 2,3-dihydro-1H-indene epimers, rac-indidene A (rac-1), indidenes B and C (2, 3); four new coumarin glucosides (4-7); and four known coumarin glucosides (8-11) were isolated from the bark of Streblus indicus (Bur.) Corner. The structures of 1-11 were defined by physical data analyses, including MS, NMR, and single-crystal X-ray diffraction. The absolute configurations of the 2,3-dihydro-1H-indene derivatives were defined via experimental and calculated ECD data. rac-Indidene A and indidenes B and C showed inhibitory activity against A549 and MCF-7 tumor cells with IC₅₀ values in the range of 2.2 ± 0.1 to 7.2 ± 0.9 μM.

Antitumor activity and antioxidant status of Streblus asper bark against Dalton's ascitic lymphoma in mice

Streblus asper Lour (Moraceae), commonly known as Siamee Rough Brush in English is widely distributed in subtropical Asia and traditionally used for several medicinal purposes. In the present study, the ethyl acetate fraction of the methanol extract from Streblus asper bark (EASA) was evaluated for antitumor effect against Dalton's ascitic lymphoma (DAL) in Swiss albino mice. Twenty-four hours after intraperitoneal inoculation of DAL cells in mice, EASA was administered intraperitoneally at 200 and 400 mg/kg body weight for 9 consecutive days. On the 10th day, half of the mice were sacrificed to determine the tumor growth parameters, and the rest were kept alive for survival assessment. Hematological, serum biochemical and tissue (liver, kidney) antioxidant profiles were also determined. EASA exhibited significant and dose dependent decrease in tumor growth parameters and increased survival of DAL bearing animals. EASA significantly and dose-dependently normalized the altered hematological, serum biochemical and tissue antioxidant parameters as compared with the DAL control mice. From the present study it may be concluded that S. asper bark possesses remarkable antitumor efficacy mediated by amelioration of oxidative stress by multiple mechanisms.

Protective Effects of Streblus asper Leaf Extract on H2O2-Induced ROS in SK-N-SH Cells and MPTP-Induced Parkinson's Disease-Like Symptoms in C57BL/6 Mouse

This study investigated the effects of Streblus asper leaf extract (SA) on reactive oxygen species (ROS) in SK-N-SH cell culture and on motor functions and behaviors in MPTP-treated C57BL/6 mice. SK-N-SH cell viability after incubation with SA for 24 h was measured by MTT assay. Intracellular ROS levels of SK-N-SH cells were quantified after pretreatment with SA (0, 200, 600, and 1000 µg/mL) in the presence of H₂O₂ (300 µM). Male C57BL/6 mice were force-fed with water or 200 mg/kg/day SA for 32 days. Intraperitoneal injection of MPTP was used to induce Parkinson's disease-like symptoms. Catalepsy, beam balance ability, olfactory discrimination, social recognition, and spontaneous locomotor activity were assessed on days 19, 21, 23, 26, and 32, respectively. In cell culture, SA at 200, 600, and 1000 µg/mL significantly decreased ROS levels in H₂O₂-treated SK-N-SH cells. MPTP-treated C57BL/6 mice showed a significant change in all parameters tested when compared to the control group. Pretreatment and concurrent treatment with 200 mg/kg/day SA could antagonize the motor and cognitive function deficits induced by MPTP. The results show that SA possesses anti-Parkinson effects in MPTP-treated C57BL/6 mice and that reduction in ROS levels might be one of the mechanisms.

Antidiabetic plants used among the ethnic communities of Unakoti district of Tripura, India

ETHNOPHARMACOLOGICAL RELEVANCE

A large group of ethnic communities living in Unakoti district of Tripura, India is still dependent on traditional herbal remedies for treatment of diabetes. Valuable information collected from these communities in the present investigation is important in maintaining their indigenous knowledge of folklore medicine.

METHODS

Systematic and extensive field surveys were conducted during 2011-2013 among the ethnic inhabitants of Unokati district, Tripura, India covering all the seasons to collect information on their traditional herbal medication system for treatment of diabetes. Obtained data were analysed through fidelity level (FL), use value (UV) and relative frequency of citation (RFC) to authenticate the uniqueness of the species being used for diabetes treatment.

RESULTS

In this current study a total of 39 medicinal plant species belonging to 37 genera and 28 families were presented, used by the traditional healers of Unakoti district, Tripura, India for diabetes treatment. FL, UV and RFC values of collected plants for the selected study area ranges between 06% and 100%, 0.07% and 2.64% and 0.02% and 0.51% respectively. Out of 39 collected plants, 11, 5 and 3 plant species have showed significant (<50%) FL, UV and RFC values respectively.

CONCLUSION

Like many other ethnic communities of the world, inhabitants of Unakoti district depend on a traditional medication system to treat diabetes. Documented floras are locally available and need proper further pharmacological validation to endorse their traditional use in a modern health care system. This will help in the development of effective herbal antidiabetic medicines in near future.

Antioxidant Activity and Phenolic Content of Streblus asper Leaves from Various Drying Methods

Aqueous and ethanol extracts of oven and freeze-dried Streblus asper leaves were investigated using DPPH assay. The presence of phenolic compounds and flavonoids in the extracts, which were detected by Folin and colorimetric assays, respectively, may be responsible for the antioxidant activities of S. asper. The different drying treatments resulted in significant differences (p < 0.05) in the antioxidant properties as well as the phenolic and flavonoid contents of the S. asper extracts. Freeze-dried S. asper leaf extracts exhibited high DPPH radical scavenging activity ranging from 69.48% ± 0.03% to 89.25% ± 0.01% at concentrations ranging from 0 to 1 mg/mL, significantly higher compared with the oven-dried extracts which were in the range of 68.56% ± 0.01% to 86.68% ± 0.01%. Generally, the 70% ethanol extract of the freeze-dried samples exhibited higher phenolic and flavonoid content than the aqueous extract, with values of 302.85 ± 0.03 mg GAE/g and 22.70 ± 0.02 mg QE/g compared with 226.8 ± 0.03 mg GAE/g and 15.38 ± 0.05 mg QE/g, respectively. This study showed that S. asper leaf extracts contain a number of health promoting bioactive compounds, such as phenolic compounds, and are potential sources of natural antioxidants.

Antidiabetic effect of Streblus asper in streptozotocin-induced diabetic rats

CONTEXT

In the Indian traditional system of medicine, Streblus asper Lour (Moraceae) is prescribed for the treatment of diabetes mellitus.

OBJECTIVE

In the present study, α-amyrin acetate isolated from S. asper, and the petroleum ether extract of S. asper stem bark (PESA) was screened for their antidiabetic properties in streptozotocin (STZ)-induced diabetic rats.

MATERIALS AND METHODS

Successive Soxhlet extraction of the dried stem bark with petroleum ether and then with ethanol (95%) yielded petroleum ether and ethanol extracts, respectively, which were concentrated under reduced pressure. Hyperglycemia was induced in rats by STZ (50 mg/kg, b.w.). Twenty-four hours after STZ induction, respective groups of diabetic rats received PESA (100, 250 and 500 mg/kg, b.w.) and α-amyrin acetate (25, 50 and 75 mg/kg, b.w.) respectively, orally daily for 15 days. Glibenclamide (0.5 mg/kg, orally) served as a reference. Blood glucose levels were measured on every 5th day during the 15 days of treatment. The serum lipid profiles and biochemical parameters, viz., serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP), insulin and glycosylated hemoglobin level, were measured.

RESULTS

PESA significantly (p < 0.01) normalized blood-glucose levels and serum biochemical parameters as compared with those of STZ controls. α-Amyrin acetate (75 mg/kg, b.w.) exhibited maximum glucose lowering effect (71.10%) in diabetic rats compared to the other dose (25, 50 mg/kg) at the end of the study. The protective effect was further confirmed by histopathological examination of the liver.

CONCLUSION

PESA and α-amyrin acetate demonstrated remarkable antidiabetic activity in STZ-induced diabetic rats.

'Heat-treatment aqueous two phase system' for purification of serine protease from Kesinai (Streblus asper) leaves

A ‘Heat treatment aqueous two phase system’ was employed for the first time to purify serine protease from kesinai (Streblus asper) leaves. In this study, introduction of heat treatment procedure in serine protease purification was investigated. In addition, the effects of different molecular weights of polyethylene glycol (PEG 4000, 6000 and 8000) at concentrations of 8, 16 and 21% (w/w) as well as salts (Na-citrate, MgSO₄ and K₂HPO₄) at concentrations of 12, 15, 18% (w/w) on serine protease partition behavior were studied. Optimum conditions for serine protease purification were achieved in the PEG-rich phase with composition of 16% PEG6000-15% MgSO₄. Also, thermal treatment of kesinai leaves at 55 °C for 15 min resulted in higher purity and recovery yield compared to the non-heat treatment sample. Furthermore, this study investigated the effects of various concentrations of NaCl addition (2, 4, 6 and 8% w/w) and different pH (4, 7 and 9) on the optimization of the system to obtain high yields of the enzyme. The recovery of serine protease was significantly enhanced in the presence of 4% (w/w) of NaCl at pH 7.0. Based on this system, the purification factor was increased 14.4 fold and achieved a high yield of 96.7%.

Optimization of the conditions for extraction of serine protease from kesinai plant (Streblus asper) leaves using response surface methodology

Response surface methodology (RSM) using a central composite design (CCD) was employed to optimize the conditions for extraction of serine protease from kesinai (Streblus asper)leaves. The effect of independent variables, namely temperature (42.5,47.5, X₁), mixing time (2–6 min, X₂), buffer content (0–80 mL, X₃) and buffer pH (4.5–10.5, X₄) on specific activity, storage stability, temperature and oxidizing agent stability of serine protease from kesinai leaves was investigated. The study demonstrated that use of the optimum temperature, mixing time, buffer content and buffer pH conditions protected serine protease during extraction, as demonstrated by low activity loss. It was found that the interaction effect of mixing time and buffer content improved the serine protease stability, and the buffer pH had the most significant effect on the specific activity of the enzyme. The most desirable conditions of 2.5 °C temperature, 4 min mixing time, 40 mL buffer at pH 7.5 was established for serine protease extraction from kesinai leaves.

Comparison of the sedative and hypnotic effects of flavonoids, saponins, and polysaccharides extracted from Semen Ziziphus jujube

Semen Ziziphus jujube (SZJ), the seeds of Ziziphus jujuba Mill. var. spinosa, is a kind of traditional Chinese medicine used for its action on insomnia. In order to analyze the effective component, we investigated and compared the sedative and hypnotic effects of three kinds of compounds, flavonoids, saponins, and polysaccharides. Flavonoids, saponins, and polysaccharides were extracted from SZJ and orally administered to mice separately at 17 g kg(-1) per day for certain days before animal tests. Spontaneous motility and coordinated movement tests were used to observe the effects of the three kinds of compounds on the mouse behavior, and sodium barbital-induced sleeping time of mouse were tested to analyze the effects of the three kinds of compounds on the sleep of mouse. Results show that flavonoids and saponins caused a significant reduction of walking time and coordinated movement ability of mouse, significantly prolonged its sleeping time at 40 mg kg(-1), ip, subthreshold dose and increased the sleeping number of animals at 50 mg kg(-1), ip, superthreshold dose induced by coeliac injection of sodium barbital. Polysaccharides did not show any significance in all animal tests. Comparative analysis showed that saponins had a more effective sedative and hypnotic function than that of flavonoids, polysaccharides did not show a sedative and hypnotic effect.