Secondary Metabolites of Plants from the Genus Saussurea: Chemistry and Biological Activity

Current and potential future biological uses of Saussurea costus (Falc.) Lipsch: A comprehensive review

Background

Saussurea costus (S. costus) is a critically endangered medicinal plant that has been extensively studied for its chemical composition, significance, and therapeutic potential as traditional phytomedicine. This comprehensive review aims to provide a thorough understanding of S. costus, including its biological activities, chemical makeup, and potential therapeutic uses in biotechnology.

Objectives

This study investigated the pharmacological properties of S. costus, including its antimicrobial, antioxidant, and antifungal properties, and its usefulness in treating conditions such as thyroid disorders and liver injury. This study also aimed to assess and improve the techniques used to extract bioactive compounds and to develop effective methods for harvesting these compounds from medicinal plants.

Methods

This review analyzed the available literature on the phytochemical makeup and bioactivity of S. costus extract using techniques such as molecular docking against SARS-CoV-2 protease, green extraction methods, and phytochemical analysis.

Results

This review revealed that S. costus possesses various pharmacological properties, including antimicrobial, antiviral, anti-inflammatory, and anticancer activities. It is effective in combating fungal infections, reducing inflammation, treating cancer, and inhibiting viral replication, and has the potential to control Candida species. Moreover, S. costus has been explored for its capacity to synthesize nanoparticles with antimicrobial properties and for its potential in treating thyroid disorders and liver injury.

Recommendations

Despite promising results, additional research is necessary to fully comprehend the benefits of S. costus and validate its effectiveness in clinical settings. Future research should focus on standardized methodologies and rigorous clinical trials to confirm the safety and effectiveness of S. costus in various medical fields as well as further investigate its biotechnological and pharmaceutical applications.

Rutin-Loaded Transethosomal Gel for Topical Application: A Comprehensive Analysis of Skin Permeation and Antimicrobial Efficacy

This study conducts a systematic investigation of the creation and optimization of a rutin-loaded transethosome intended for topical use. The formulation's characteristics were thoroughly assessed for vesicle size (160.45 ± 1.98 nm), polydispersity index (0.235 ± 0.067), and zeta potential (-22.89 mV), with an entrapment efficiency and drug loading of 89.99 ± 1.55% and 8.9 ± 2.11%, respectively, and found to have a spherical shape by the use of transmission electron microscopy. The conversion to a gel suitable for application on the skin was carried out. The drug release form Opt-RUT-TE formulation (73.61 ± 2.55%) was significantly higher than that of release form RUT-suspension (34.52 ± 1.19%). The drug that permeated the skin from Opt-RUT-TEG (935.25 ± 10.49 μg/cm2) was significantly higher than the permeability from RUT-Suspension gel (522.57 ± 6.79 μg/cm2). Notably, tape stripping analysis revealed that the Opt-RUT-TE gel effectively penetrated the skin layers, with a higher concentration observed in the epidermis-dermis than in the RUT-suspension gel. The transethosomal gel exhibited favorable characteristics, highlighting its capacity to efficiently permeate the skin and suppress the growth of microorganisms, and Opt-RUT-TEG showed a higher microorganism inhibition zone (Gram-positive bacteria) than that of RUT-suspension gel. The investigation highlights the significant therapeutic possibilities of rutin in a transethosomal gel formulation for treating dermatological diseases by improving skin permeability and exhibiting antibacterial effects.

Saussurea costus (Falc.) Lipsch.: a comprehensive review of its pharmacology, phytochemicals, ethnobotanical uses, and therapeutic potential

Saussurea costus (Falc.) Lipsch., commonly known as costus, is a perennial herb that has been traditionally used in various indigenous medicinal systems across Asia. Its historical prominence in traditional remedies underscores the need to explore its phytochemical composition, pharmacological properties, and potential therapeutic benefits. This review aims to provide a comprehensive overview of the available literature on the pharmacological properties, phytochemical constituents, ethnobotanical uses, and therapeutic potential of S. costus. An exhaustive search was performed across multiple electronic databases, including PubMed/MedLine, Google Scholar, Web of Science, Scopus, TRIP database, and Science Direct. Both experimental and clinical studies, as well as traditional ethnobotanical records, were considered for inclusion. The phytochemical analysis revealed that S. costus contains a plethora of bioactive compounds, including sesquiterpenes, flavonoids, and essential oils, which are responsible for its myriad of medicinal properties. The pharmacological studies have demonstrated its anti-inflammatory, anti-oxidant, anti-cancer, hepatoprotective, and immunomodulatory effects, among others. Ethnobotanical data showcased its extensive use in treating ailments like asthma, digestive disorders, and skin conditions. Some clinical trials also underscore its efficacy in certain health conditions, corroborating its traditional uses. S. costus possesses significant therapeutic potential, largely attributable to its rich phytochemical composition; the convergence of its traditional uses and modern pharmacological findings suggests promising avenues for future research, especially in drug development and understanding its mechanism of action in various ailments.

Costunosides A-C: cytotoxic sesquiterpene lactones from the rhizomes of Aucklandia costus Falc

Three new eudesmane type rare sesquiterpene lactone galactosides, costunosides A-C (1-3) were isolated from the rhizomes of Aucklandia costus along with ten known compounds (4-13). Costunosides A-C (1-3) are the first example of naturally eudesmane glycosides containing a β-galactopyranoside moiety. The structure and relative configurations of these compounds were established by comprehensive analysis of MS and, in particular 1D/2D NMR spectroscopic data. The isolated compounds were tested against a panel of human cancer cell lines, where compounds 3, 6 and 7 have shown promising cytotoxic activity against PC-3, HCT-116 and A549 cell lines with IC50 values in the range of 3.4 µM to 9.3 µM, respectively. Costunosides A-C (1-3) were also screened for inhibition assay of acetyl-cholinesterase (AChE), and butyrylcholinesterase (BChE) and found inactive at a concentration of 10 µM.

Immunomodulatory Activity of Polysaccharides Isolated from Saussurea salicifolia L. and Saussurea frolovii Ledeb

The genus Saussurea has been used in the preparation of therapies for a number of medical problems, yet not much is known about the therapeutic high-molecular-weight compounds present in extracts from these plants. Since polysaccharides are important in immune modulation, we investigated the chemical composition and immunomodulatory activity of Saussurea salicifolia L. and Saussurea frolovii Ledeb polysaccharides. Water-soluble polysaccharides from the aerial parts of these plants were extracted using water at pHs of 2 and 6 and subsequently precipitated in ethanol to obtain fractions SSP2 and SSP6 from S. salicifolia and fractions SSF2 and SSF6 from S. frolovii. The molecular weights of fractions SSP2, SSP6, SFP2, and SFP6 were estimated to be 143.7, 113.2, 75.3, and 64.3 kDa, respectively. The polysaccharides from S. frolovii contained xylose (67.1-71.7%) and glucose (28.3-32.9%), whereas the polysaccharides from S. frolovii contained xylose (63.1-76.7%), glucose (11.8-19.2%), galactose (4.7-8.3%), and rhamnose (6.8-9.4%). Fractions SSP2, SSP6, and SFP2 stimulated nitric oxide (NO) production by murine macrophages, and NO production induced by SSP2, SSP6, and SFP2 was not inhibited by polymyxin B treatment of the fractions, whereaspolymyxin B treatment diminished the effects of SFP6, suggesting that SFP6 could contain lipopolysaccharide (LPS). The LPS-free fractions SSP2, SSP6, and SFP2 had potent immunomodulatory activity, induced NO production, and activated transcription factors NF-κB/AP-1 in human monocytic THP-1 cells and cytokine production by human MonoMac-6 monocytic cells, including interleukin (IL)-1α, IL-1β, IL-6, granulocyte macrophage colony-stimulating factor (GM-CSF), interferon-γ, monocyte chemotactic protein 1 (MCP-1), and tumor necrosis factor (TNF). These data suggest that at least part of the beneficial therapeutic effects reported for water extracts of the Saussurea species are due to the modulation of leukocyte functions by polysaccharides.

Assessment of Genetic Diversity and Genetic Structure of Saussurea medusa (Asteraceae), a "Sky Island" Plant in the Qinghai-Tibet Plateau, Using SRAP Markers

Saussurea medusa Maxim. is a typical "sky island" species and one with the highest altitude distributions among flowering plants. The present study aimed at analyzing the genetic diversity and population structure of 300 S. medusa accessions collected from 20 populations in the Qilian Mountains in the northeastern Qinghai-Tibet Plateau (QTP), using sequence-related amplified polymorphism (SRAP) markers. A total of 14 SRAP primer combinations were employed to analyze genetic diversity and population structure across all accessions. Out of 511 amplified bands, 496 (97.06%) were polymorphic. The populations in the eastern Qilian Mountains had significantly higher genetic diversity than those in the central and western groups. Population structure analysis revealed greater genetic differentiation among populations with a Gst of 0.4926. UPGMA-based clustering classified the 300 S. medusa accessions into 3 major clusters, while the Bayesian STRUCTURE analysis categorized them into 2 groups. Correlation analyses showed that the genetic affinity of the populations was based on differences in geographical distance, moisture conditions, and photothermal conditions between the habitats. This study represents the first comprehensive genetic assessment of S. medusa and provides important genetic baseline data for the conservation of the species.

HPLC-PDA Method for Quantification of Bioactive Compounds in Crude Extract and Fractions of Aucklandia costus Falc. and Cytotoxicity Studies against Cancer Cells

Aucklandia costus Falc. (Synonym: Saussurea costus (Falc.) Lipsch.) is a perennial herb of the family Asteraceae. The dried rhizome is an essential herb in the traditional systems of medicine in India, China and Tibet. The important pharmacological activities reported for Aucklandia costus are anticancer, hepatoprotective, antiulcer, antimicrobial, antiparasitic, antioxidant, anti-inflammatory and anti-fatigue activities. The objective of this study was the isolation and quantification of four marker compounds in the crude extract and different fractions of A. costus and the evaluation of the anticancer activity of the crude extract and its different fractions. The four marker compounds isolated from A. costus include dehydrocostus lactone, costunolide, syringin and 5-hydroxymethyl-2-furaldehyde. These four compounds were used as standard compounds for quantification. The chromatographic data showed good resolution and excellent linearity (r² ˃ 0.993). The validation parameters, such as inter- and intraday precision (RSD < 1.96%) and analyte recovery (97.52-110.20%; RSD < 2.00%),revealed the high sensitivity and reliability of the developed HPLC method. The compounds dehydrocostus lactone and costunolide were concentrated in the hexane fraction (222.08 and 65.07 µg/mg, respectively) and chloroform fraction (99.02 and 30.21 µg/mg, respectively), while the n-butanol fraction is a rich source of syringin (37.91 µg/mg) and 5-hydroxymethyl-2-furaldehyde (7.94 µg/mg). Further, the SRB assay was performed for the evaluation of anticancer activity using lung, colon, breast and prostate cancer cell lines. The hexane and chloroform fractions show excellent IC₅₀ values of 3.37 ± 0.14 and 7.527 ± 0.18 µg/mL, respectively, against the prostate cancer cell line (PC-3).

3'-Demethoxy-6-O-Demethylisoguaiacin and Norisoguaiacin Nematocidal Lignans from Artemisia cina against Haemonchus contortus Infective Larvae

Artemisia cina is a plant used in traditional Chinese medicine as a remedy for parasitic diseases. This study describes the isolation and chemical characterization of anthelmintic compounds of A. cina against Haemonchus contortus infective larvae (L₃) through lethal testing. Previously, three extracts-n-hexane (HexAc), ethyl acetate (EtOAc) and methanol (MeOAc)-were evaluated at concentrations of 4 to 0.5 mg/mL, resulting in the HexAc extract with the greatest effect of 76.6% mortality of the larvae at 4 mg/mL. Then, this was chemically fractioned by polarity, obtaining seven fractions (C1F1-C1F7), and, when evaluated at concentrations from 2 to 0.25 mg/mL, the 2 mg/mL C1F5 fraction produced an effect against the nematode H. contortus of 100% mortality of the larvae. Thus, this fraction was fractionated again by column chromatography, obtaining twelve subfractions (C2F1-C2F12) which were evaluated from 1 to 0.125 mg/mL, with the C2F5 subfraction causing a nematicidal effect of 100% mortality. NMR analysis of one (¹H, ¹³C and DEPT) and two dimensions (COSY, HSQC and HMBC) and mass spectrometry of this fraction allowed us to identify the mixture of 3'-demethoxy-6-O-demethylisoguaiacin and norisoguaiacin. Therefore, it can be assumed that the mixture of these compounds is responsible for the anthelmintic effect. These results indicate that A. cina containing anthelmintic compounds and might be used as an antiparasitic drug against H. contortus.

Antiplasmodial Activity of 80% Methanolic Extract and Solvent Fractions of Stem Bark of Acacia tortilis in Swiss Albino Mice

Background

Malarial infection has significant negative impact on the health of the world population. It is treated by modern and traditional medicines. Among traditional medicinal plants, Acacia tortilis is used by different communities as antimalarial agent. Therefore, the objective of this study is to validate antimalarial activity of the stem bark of Acacia tortilis in mice.

Methods

To evaluate antimalarial activity of the plant, 4-day suppressive, curative, and prophylactic antimalarial test models were used. Parasitemia, packed cell volume (PCV), survival time, rectal temperature, and body weight were used to evaluate the effect of the plant extracts. Data were analyzed using SPSS version 26 followed by Tukey's post hoc multiple comparison test.

Results

The crude extract and dichloromethane fraction significantly suppressed the level of parasitemia (p < 0.001) and increased mean survival time (p < 0.01) at all tested doses. Similarly, significant effects were observed in mean survival time, % change of PCV, weight, and temperature in both curative and prophylactic antimalarial test models.

Conclusions

The methanolic extract and solvent fractions of the stem bark of Acacia tortilis has shown antimalarial activity, and the finding supports the traditional use and the in vitro studies. Thus, this study can be used as an initiation for researchers to find the most active phytochemical entity and to conduct additional safety and efficacy tests.

Evaluation of the Antihyperglycemic and Antihyperlipidemic Activity of Saussurea hypoleuca Root in Alloxan-Induced Diabetes in Rat Model and Correlation to Its Major Secondary Metabolites

Saussurea hypoleuca belongs to the family Asteraceae, which has previously shown hepatoprotective, anticancer, and antioxidant activity. This study aimed to evaluate the antihyperglycemic and antihyperlipidemic activity of its root methanol extract and various fractions for the first time. This was performed using alloxan-induced diabetes in the rat model for both short, and long-term periods using different administration doses. Different biochemical parameters were studied and further consolidated by histopathological examination and in silico molecular modeling. The results showed that in the long-term study, at a dose of 400 mg/kg b.wt, the ethyl acetate fraction caused a pronounced reduction in fasting blood glucose level (FBG) and glycated hemoglobin (HbA_1c) by 77.2% and 36.8%, respectively, compared to the diabetic group. This was confirmed by the histopathological examination of the animals’ pancreatic sections. The ethyl acetate fraction also showed a reduction in total cholesterol (TC), total glycerides (TG), and low-density lipoprotein cholesterol (LDL-C) levels. It improved kidney and liver functions, causing a reduction in aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine transaminase (ALT), urea, and creatinine levels. This is mainly attributed to its richness in secondary metabolites. Molecular docking showed that all the tested compounds showed certain inhibitory potential towards human α-glucosidase (HAG) and ATP citrate lyase (ACL). Thus, Saussurea hypoleuca roots can help in the management of hyperglycemia, hyperlipidemia, and hepatic and kidney dysfunction.

Hairy Root Cultures as a Source of Polyphenolic Antioxidants: Flavonoids, Stilbenoids and Hydrolyzable Tannins

Due to their chemical properties and biological activity, antioxidants of plant origin have gained interest as valuable components of the human diet, potential food preservatives and additives, ingredients of cosmetics and factors implicated in tolerance mechanisms against environmental stress. Plant polyphenols are the most prominent and extensively studied, albeit not only group of, secondary plant (specialized) metabolites manifesting antioxidative activity. Because of their potential economic importance, the productive and renewable sources of the compounds are desirable. Over thirty years of research on hairy root cultures, as both producers of secondary plant metabolites and experimental systems to investigate plant biosynthetic pathways, brought about several spectacular achievements. The present review focuses on the Rhizobium rhizogenes-transformed roots that either may be efficient sources of plant-derived antioxidants or were used to elucidate some regulatory mechanisms responsible for the enhanced accumulation of antioxidants in plant tissues.

Lanicepines A and B, Sesquiterpenes with Amino Acid-Derived Substituents from the Flowering Aerial Parts of Saussurea laniceps

Two new guaianolide sesquiterpenes, lanicepines A (1) and B (2), possessing unusual amino acid-derived substituents at C-13, were isolated from the flowering aerial parts of Saussurea laniceps, a traditional herbal medicine also known as "snow lotus". The structures of 1 and 2 were elucidated based on spectroscopic analysis including applications of the modified Mosher's method and Marfey's method as well as ECD calculations. Lanicepine A (1) contains a dihydropyridinone moiety with a carbamoyl and a hydroxymethyl group. This substituent was considered to consist of asparagine and a C₄ unit. In contrast, lanicepine B (2) has a substituent that seems to be derived from l-proline and a C₄ unit. Lanicepines A (1) and B (2) and two related known sesquiterpenes isolated from the same plant material, 11β,13-dihydrodesacylcynaropicrin (3) and 11β,13-dihydrodesacylcynaropicrin 8-O-β-d-glucoside (4), demonstrated inhibitory activity against IL-1β production from LPS-stimulated microglial cells.

Study of the Antimalarial Activity of the Leaf Extracts and Fractions of Persea americana and Dacryodes edulis and Their HPLC Analysis

In the present study, the antimalarial activity of the extracts and fractions of the leaves of Persea americana and Dacryodes edulis as well as their phytochemical compositions were examined. Each of the extracts of the plants was successively fractionated to obtain hexane, ethyl acetate, methanol, and water fractions. The extracts and fractions were tested against Plasmodium berghei in both curative and suppressive antimalarial mouse models. Their major phytochemical composition was studied by the standard chemical tests and HPLC analysis. The extracts and fractions of P. americana and D. edulis demonstrated significant (p < 0.05) maximal plasmodial inhibition as 52.16 ± 2.77% and 57.10 ± 1.98%, respectively, and chemosuppression of parasitemia as 64.01 ± 0.08% and 71.99 ± 0.06%, respectively. The major secondary metabolites identified in the plants include alkaloids, flavonoids, and saponins. It was concluded that P. americana and D. edulis possess promising antimalarial activity and they are potential sources of new lead compounds against malaria.

Effect of Herbal Formulation on Immune Response Enhancement in RAW 264.7 Macrophages

Immune response is a necessary self-defense mechanism that protects the host from infectious organisms. Many medicinal plants are popularly used in Asian folk medicine to increase body resistance. An herbal formulation named KM1608 was prepared from three medicinal plants: Saussurea lappa, Terminalia chebula, and Zingiber officinale. In this study, we evaluated the immune stimulatory effect of KM1608 on RAW 264.7 murine macrophages. Network pharmacological analyses were used to predict potential immune response pathways of major compounds from KM1608. The cytotoxicity and immuno-stimulating effect of KM1608 were determined using cell viability and nitric oxide assays. The underlying mechanism of immunomodulatory activity was evaluated by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) of pro-inflammatory cytokines. The results of network pharmacological analysis suggested that major compounds from KM1608 possess anticancer potential via immune signaling pathways. After treatment with KM1608 at 25–100 µg/mL for 24 h, the level of nitric oxide was increased in the dose-dependent manner. The results of quantitative real-time PCR showed that KM1608 stimulates the expression of immune cytokines (interferon (IFN)-α, -β, IL-1β, -6, IL-10, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2)) in macrophages. KM1608 extract is a potential agent for immune response enhancement.

Antimalarial efficacy of Pongamia pinnata (L) Pierre against Plasmodium falciparum (3D7 strain) and Plasmodium berghei (ANKA)

Background

The objective of the current study was to assess the in vitro antiplasmodial activities of leaf, bark, flower, and the root of Pongamia pinnata against chloroquine-sensitive Plasmodium falciparum (3D7 strain), cytotoxicity against Brine shrimp larvae and THP-1 cell line. For in vivo study, the plant extract which has shown potent in vitro antimalarial activity was tested against Plasmodium berghei (ANKA strain).

Methods

The plant Pongamia pinnata was collected from the herbal garden of Acharya Nagarjuna University of Guntur district, Andhra Pradesh, India. Sequentially crude extracts of methanol (polar), chloroform (non-polar), hexane (non-polar), ethyl acetate (non-polar) and aqueous (polar) of dried leaves, bark, flowers and roots of Pongamia pinnata were prepared using Soxhlet apparatus. The extracts were screened for in vitro antimalarial activity against P. falciparum 3D7 strain. The cytotoxicity studies of crude extracts were conducted against Brine shrimp larvae and THP-1 cell line. Phytochemical analysis of the plant extracts was carried out by following the standard methods. The chemical injury to erythrocytes due to the plant extracts was checked. The in vivo study was conducted on P. berghei (ANKA) infected BALB/c albino mice by following 4-Day Suppressive, Repository, and Curative tests.

Results

Out of all the tested extracts, the methanol extract of the bark of Pongamia pinnata had shown an IC₅₀ value of 11.67 μg/mL with potent in vitro antimalarial activity and cytotoxicity evaluation revealed that this extract was not toxic against Brine shrimp and THP-1 cells. The injury to erythrocytes analysis had not shown any morphological alterations and damage to the erythrocytes after 48 h of incubation. Because methanolic bark extract of Pongamia pinnata has shown good antimalarial activity in vitro, it was also tested in vivo. So the extract had exhibited an excellent activity against P. berghei malaria parasite while decrement of parasite counts was moderately low and dose-dependent (P < 0.05) when compared to the control groups, which shown a daily increase of parasitemia, unlike the CQ-treated groups. The highest concentration of the extract (1000 mg/kg b.wt./day) had shown 83.90, 87.47 and 94.67% of chemo-suppression during Suppressive, Repository, and Curative tests respectively which is almost nearer to the standard drug Chloroquine (5 mg/kg b.wt./day). Thus, the study has revealed that the methanolic bark extract had shown promisingly high ((P < 0.05) and dose-dependent chemo-suppression. The phytochemical screening of the crude extracts had shown the presence of alkaloids, flavonoids, triterpenes, tannins, carbohydrates, phenols, coumarins, saponins, phlobatannins and steroids.

Conclusions

The present study is useful to develop new antimalarial drugs in the scenario of the growing resistance to the existing antimalarials. Thus, additional research is needed to characterize the bioactive molecules of the extracts of Pongamia pinnata that are responsible for inhibition of malaria parasite.

Chemical constituents from the genus Saussurea and their biological activities

The genus

Saussurea involucrata: A review of the botany, phytochemistry and ethnopharmacology of a rare traditional herbal medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Saussurea involucrata Matsum. & Koidz. is an endangered species of the Asteraceae family, growing in the high mountains of central Asia. It has been, and is, widely used in traditional Uyghur, Mongolian and Kazakhstan medicine as well as in Traditional Chinese Medicine as Tianshan Snow Lotus (Chinese: ). In traditional medical theory, S. involucrata can promote blood circulation, thereby alleviating all symptoms associated with poor circulation. It also reputedly eliminates cold and dampness from the body, diminishes inflammation, invigorates, and strengthens Yin and Yang. It has long been used to treat rheumatoid arthritis, cough with cold, stomach ache, dysmenorrhea, and altitude sickness in Uyghur and Chinese medicine.

AIM OF THE REVIEW

To comprehensively summarize the miscellaneous research that has been done regarding the botany, ethnopharmacology, phytochemistry, biological activity, and toxicology of S. involucrata.

METHOD

An extensive review of the literature was carried out. Apart from different electronic databases including SciFinder, Chinese National Knowledge Infrastructure (CNKI), ScienceDirect that were sourced for information, abstracts, full-text articles and books written in English and Chinese, including those traditional records tracing back to the Qing Dynasty. Pharmacopoeia of China and other local herbal records in Uighur, Mongolian and Kazakhstan ethnomedicines were investigated and compared for pertinent information.

RESULTS

The phytochemistry of S. involucrata has been comprehensively investigated. More than 70 compounds have been isolated and identified; they include phenylpropanoids, flavonoids, coumarins, lignans, sesquiterpenes, steroids, ceramides, polysaccharides. Scientific studies on the biological activity of S. involucrata are equally numerous. The herb has been shown to have anti-neoplastic, anti-inflammatory, analgesic, anti-oxidative, anti-fatigue, anti-aging, anti-hypoxic, neuroprotective and immunomodulating effects. Many have shown correlations to the traditional clinical applications in Traditional Chinese Medicine and medicines. The possible mechanisms of S. involucrata in treating various cancers are revealed in the article, these include inhibition of cancer cells by affecting their growth, adhesion, migration, aggregation and invasion, inhibition of epidermal growth factor receptor signaling in cancer cells, hindrance of cancer cell proliferation, causing cytotoxicity to cancer cells and promoting expression of tumor suppressor genes. Dosage efficacy is found to be generally concentration- and time-dependent. However, studies on the correlation between particular chemical constituents and specific bioactivities are limited.

CONCLUSION

In this review, we have documented the existing traditional uses of S. involucrata and summarized recent research into the phytochemistry and pharmacology of S. involucrata. Many of the traditional uses have been validated by phytochemical and modern pharmacological studies but there are still some areas where the current knowledge could be improved. Although studies have confirmed that S. involucrata has a broad range of bioactivities, further in-depth studies on the exact bioactive molecules and the mechanism of action are expected. Whether we should use this herb independently or in combination deserves to be clarified. The exact quality control as well as the toxicology studies is necessary to guarantee the stability and safety of the clinic use. The sustainable use of this endangered resource was also addressed. In conclusion, this review was anticipated to highlight the importance of S. involucrata and provides some directions for the future development of this plant.

Antibiotic additive and synergistic action of rutin, morin and quercetin against methicillin resistant Staphylococcus aureus

Background

To determine the effect of flavonoids in conjunction with antibiotics in methicillin resistant Staphylococcus aureus (MRSA) a study was designed. The flavonoids included Rutin, Morin, Qurecetin while antibiotics included ampicillin, amoxicillin, cefixime, ceftriaxone, vancomycin, methicillin, cephradine, erythromycin, imipenem, sulphamethoxazole/trimethoprim, ciprofloxacin and levolfloxacin. Test antibiotics were mostly found resistant with only Imipenem and Erythromycin found to be sensitive against 100 MRSA clinical isolates and S. aureus (ATCC 43300). The flavonoids were tested alone and also in different combinations with selected antibiotics.

Methods

Antibiotics and flavonoids sensitivity assays were carried using disk diffusion method. The combinations found to be effective were sifted through MIC assays by broth macro dilution method. Exact MICs were determined using an incremental increase approach. Fractional inhibitory concentration indices (FICI) were determined to evaluate relationship between antibiotics and flavonoids is synergistic or additive. Potassium release was measured to determine the effect of antibiotic-flavonoids combinations on the cytoplasmic membrane of test bacteria.

Results

Antibiotic and flavonoids screening assays indicated activity of flavanoids against test bacteria. The inhibitory zones increased when test flavonoids were combined with antibiotics facing resistance. MICs of test antibiotics and flavonoids reduced when they were combined. Quercetin was the most effective flavonoid (MIC 260 μg/ml) while morin + rutin + quercetin combination proved most efficient with MIC of 280 + 280 + 140 μg/ml. Quercetin + morin + rutin with amoxicillin, ampicillin, cephradine, ceftriaxone, imipenem, and methicillin showed synergism, while additive relationship was indicated between morin + rutin and amoxicillin, cephradine, ceftriaxone, imipenem, and methicillin. Quercetin alone had an additive effect with ampicillin, cephradine, ceftriaxone, imipenem, and methicillin. Potassium leakage was highest for morin + rutin + quercetin that improved further in combination with imipenem. Morin and rutin alone had no activity but in combination showed activity against test bacteria.

Conclusions

The flavonoids when used in combination with antibiotics were found to increase each other activity against test bacteria. The relationship between the flavonoids and antibiotics in most of the cases was additive. However in a few cases synergism was also observed. Flavonoids alone or in combinations also damaged bacterial cell membrane.

Chemical composition and antimicrobial activity of the essential oil of Juniperus excelsa M.Bieb. growing wild in Lebanon

The essential oils (EOs) isolated from the leaves and twigs of Juniperus excelsa M.Bieb. growing wild in Lebanon were characterized, and their antimicrobial activity and antiradical capacity were evaluated. The EOs were obtained by hydrodistillation using a Clevenger-type apparatus and characterized by GC and GC/MS analyses. The antimicrobial activity was evaluated by determining minimal inhibitory concentrations (MICs) against a Gram-positive and a Gram-negative bacterium, a yeast, and a dermatophyte with the broth microdilution technique. A total of 28 constituents was identified and accounted for 90.1 and 95.6% of the twig and leaf EO composition, respectively. Both EOs were essentially composed of monoterpene hydrocarbons (46.7 and 59.6% for twig and leaf EOs, resp.) and sesquiterpenes (39.4 and 32.1%, resp.). The main components were α-pinene, α-cedrol, and δ-car-3-ene. The J. excelsa EOs did not show any antiradical potential, but revealed interesting in vitro antimicrobial activities against Staphylococcus aureus and Trichophyton rubrum (MICs of 64 and 128 μg/ml, resp.). The three major compounds were tested separately and in combination according to their respective amounts in the oil. δ-Car-3-ene was the most active component and is undoubtedly one of the constituents driving the antifungal activity of J. excelsa essential oil, even though synergies are probably involved.

Inducible expression of Arabidopsis response regulator 22 (ARR22), a type-C ARR, in transgenic Arabidopsis enhances drought and freezing tolerance

The Arabidopsis two-component signaling system, which is comprised of sensor histidine kinases, histidine phosphotransfer proteins, and response regulators, mediates cytokinin response as well as various other plant responses including abiotic stress responses. Arabidopsis response regulators (ARRs) are classified into type-A, -B, and -C. Although the roles of type-A and -B ARRs are well established in Arabidopsis plant signaling, roles of type-C ARRs, ARR22 and ARR24, remain elusive. ARR22, a preferentially cytosolic protein, interacts with certain Arabidopsis histidine phosphotransfer proteins (AHPs) and displays phosphatase activity on AHP5. ARR22 is induced by cold and dehydration. Here, we show that inducible overexpression of ARR22 in Arabidopsis enhanced dehydration, drought, and cold tolerance in a dexamethasone-dependent manner, whereas mutation of the putative phospho-accepting Asp to Asn in ARR22 (ARR22^D74N) abolished these tolerance phenotypes. Overexpression of ARR22 decreased electrolyte leakage in dehydration-, drought-, or cold-stressed transgenic Arabidopsis plants compared with that of ARR22^D74N or compared with wild-type plants. Transpiration rates and stomatal apertures were not affected by ARR22 overexpression. No significant difference in both dehydration and freezing tolerance was observed between wild-type and arr22 mutants with or without cytokinin preincubation, consistent with the lack of phenotypes of arr22 mutants in their vegetative development. Meta-profile analyses of the microarray data on ARR22-responsive genes indicate that ARR22 modulates expression of a variety of abiotic stress-responsive genes, which might contribute to increasing drought and freezing tolerance. Taken together, these results suggest that ARR22 plays a positive role in the stress tolerance response in part via enhancing cell membrane integrity and that phospho-histidine phosphatase activity of ARR22 may be required for this function.

Eight New Alkyne and Alkene Derivatives from Four Saussurea Species Collected in China

Five samples of four Saussurea species, S. hieracioides, S. stella, S. graminea, and S. tatsienensis, collected in Sichuan Province, China were studied and seven new diynes and a new alkene derivatives were isolated along with 16 known compounds. Absolute configurations of two of the new compounds were established using a modified Mosher's method.

In vivo antimalarial activity, toxicity and phytochemical screening of selected antimalarial plants

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria continues to kill over a million people each year and in many populations affected by malaria, conventional drugs are often unaffordable or inaccessible. Historically, plants have been a prominent source of antimalarial drugs. Those plants currently used by indigenous people to treat malaria should be documented and investigated as potential sources of new antimalarial drugs.

AIM OF THE STUDY

To investigate in vivo antimalarial activity, toxicity and carry out phytochemical screening of selected plants which have been used in traditional medicine for the treatment of malaria.

MATERIALS AND METHODS

Organic and water extracts of four medicinal plants used for the treatment of malaria in traditional health systems of Msambweni people in Kenya were tested for antimalarial activity against Plasmodium berghei and brine shrimp lethality. They were also screened for their major phytochemical constituents.

RESULTS

Aqueous extract of the stem bark of Adansonia digitata exhibited highest chemosuppression of parasitaemia, >60% in a murine model of Plasmodium berghei infected mice. Aqueous and organic extracts of Launaea cornuta and Zanthoxylum chalybeum were toxic to the brine shrimp (LD50<1000μg/ml) while aqueous and organic extracts of Adansonia digitata and aqueous extracts of Canthium glaucum were not toxic to brine shrimp (LD50>1000μg/ml). Phytochemical screening revealed the presence of alkaloids and flavonoids in all the crude extracts of the selected plant species studied. Sesquiterpene lactones and saponis were present in organic extracts but absent in the aqueous extracts of Adansonia digitata, Canthium glaucum, Launaea cornuta and Zanthoxylum chalybeum.

CONCLUSION

The results showed that the crude extracts of Adansonia digitata and Canthium glaucum demonstrated promising antimalarial activity and there is potential for isolation of lead compounds from their extracts.

Identification of marneral synthase, which is critical for growth and development in Arabidopsis

Plants produce structurally diverse triterpenoids, which are important for their life and survival. Most triterpenoids and sterols share a common biosynthetic intermediate, 2,3-oxidosqualene (OS), which is cyclized by 2,3-oxidosqualene cyclase (OSC). To investigate the role of an OSC, marneral synthase 1 (MRN1), in planta, we characterized a Arabidopsis mrn1 knock-out mutant displaying round-shaped leaves, late flowering, and delayed embryogenesis. Reduced growth of mrn1 was caused by inhibition of cell expansion and elongation. Marnerol, a reduced form of marneral, was detected in Arabidopsis overexpressing MRN1, but not in the wild type or mrn1. Alterations in the levels of sterols and triterpenols and defects in membrane integrity and permeability were observed in the mrn1. In addition, GUS expression, under the control of the MRN1 gene promoter, was specifically detected in shoot and root apical meristems, which are responsible for primary growth, and the mRNA expression of Arabidopsis clade II OSCs was preferentially observed in roots and siliques containing developing seeds. The eGFP:MRN1 was localized to the endoplasmic reticulum in tobacco protoplasts. Taken together, this report provides evidence that the unusual triterpenoid pathway via marneral synthase is important for the growth and development of Arabidopsis.

Structure-activity relationship of citrus polymethoxylated flavones and their inhibitory effects on Aspergillus niger

Citrus peels are rich in polymethoxylated flavones (PMFs) and are potential sources of natural preservatives. Six PMFs extracts, isolated and purified from the peels of three mandarins (Citrus reticulata) and three sweet oranges (Citrus sinensis), were identified and quantitated. Their inhibitory effects on Aspergillus niger were evaluated using a microbroth dilution assay. The Red tangerine variety exhibited the greatest antifungal activity (MIC = 0.2 mg/mL), while Jincheng showed the lowest activity (MIC = 1.8 mg/mL). An analysis of principal components was applied to the results in order to elucidate the structure-activity relationships of the citrus PMFs. The structure-activity relationship analysis revealed that, for good inhibitory effect, the 5-OH, 3-OCH₃, and 8-OCH₃ functionalities were essential, while the presence of 3-OH and 3'-OCH₃ greatly reduced inhibition. The findings of this study provide important information for the exploitation and utilization of citrus PMFs as natural biopreservatives.

Four New Guaianolides and Acetylenic Alcohol from Saussurea Katochaete Collected in China

Four new guaianolides and an acetylenic alcohol were isolated from Saussurea katochaete (Asteraceae) collected in China. The structures were determined based on the spectroscopic data including the absolute configuration by application of advanced Mosher's method.