Isoflavanones from Uraria picta and their antimicrobial activity

Role of Bioactive Compounds, Novel Drug Delivery Systems, and Polyherbal Formulations in the Management of Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is an autoimmune disorder that generally causes joint synovial inflammation as well as gradual cartilage and degenerative changes, resulting in progressive immobility. Cartilage destruction induces synovial inflammation, including synovial cell hyperplasia, increased synovial fluid, and synovial pane development. This phenomenon causes articular cartilage damage and joint alkalosis. Traditional medicinal system exerts their effect through several cellular mechanisms, including inhibition of inflammatory mediators, oxidative stress suppression, cartilage degradation inhibition, increasing antioxidants and decreasing rheumatic biomarkers. The medicinal plants have yielded a variety of active constituents from various chemical categories, including alkaloids, triterpenoids, steroids, glycosides, volatile oils, flavonoids, lignans, coumarins, terpenes, sesquiterpene lactones, anthocyanins, and anthraquinones. This review sheds light on the utilization of medicinal plants in the treatment of RA. It explains various phytoconstituents present in medicinal plants and their mechanism of action against RA. It also briefs about the uses of polyherbal formulations (PHF), which are currently in the market and the toxicity associated with the use of medicinal plants and PHF, along with the limitations and research gaps in the field of PHF. This review paper is an attempt to understand various mechanistic approaches employed by several medicinal plants, their possible drug delivery systems and synergistic effects for curing RA with minimum side effects.

Anticancer studies on methanolic extract of aerial parts of Uraria Picta (Jacq.) DC

Background

Uraria picta (Jacq.) DC is a traditional Indian herb used in the Ayurvedic system of medicine. It is an ingredient of the popular Ayurvedic formulation “Dasamoola.” It is also traditionally used as an anti-inflammatory herb in Ayurveda. The plant also has excellent antioxidant potential. Different parts of Uraria picta are useful and have diverse medicinal properties. The present investigation was done to evaluate the anticancer activity of methanolic extract of aerial parts of Uraria picta (Jacq.).

Results

Preliminary phytochemical screening of MEUP confirmed the presence of flavonoids, phenolics, glycosides, and tannins. Total phenolic and flavonoid contents in MEUP were found to be 14.6 gram equivalent of gallic acid and 0.735 gram equivalent of catechin, respectively. IC50 values of cisplatin and MEUP were found to be 8.75 μg/ml and 436.92 μg/ml, respectively. Induction of apoptosis was evident from DAPI staining showing a dose-dependent increase in apoptosis. Also, a reduction in intracellular ROS was evident from the DCFH-da assay, where a dose-dependent decrease in intracellular ROS (fluorescence) was observed. Significant reduction (P < 0.05) in tumor volume was observed in mice receiving cisplatin and MEUP at both dose levels.

Conclusion

The methanolic extract of aerial parts of Uraria picta (Jacq.) DC is effective in inhibiting tumor growth and has significant anticancer property.

A new isoflavanone from Uraria crinita

A new isoflavanone, (3S)-5,7-dihydroxy-2',3',4'-trimethoxy-6,5'-diprenylisoflavanone (1) and eight known compounds including five flavones (2-6), two triterpenes (7-8) and a steroid (9) were isolated from the whole plant of Uraria crinita (Leguminosae). The structure of 1 was elucidated by detailed spectroscopic means including IR, HR-ESI-MS, 1D and 2D NMR, and CD data. Compounds 1-9 were evaluated for their cytotoxicity against four human cancer cell lines KB (mouth epidermal carcinoma), HepG2 (hepatocellular carcinoma), Lu (lung carcinoma) and MCF7 (breast carcinoma). Compound 1 showed cytotoxic activity against the tested cell lines with IC₅₀ values of 33.2, 29.4, 59.6 and 66.8 μM, respectively.

Chyawanprash: A Traditional Indian Bioactive Health Supplement

Chyawanprash (CP) is an Ayurvedic health supplement which is made up of a super-concentrated blend of nutrient-rich herbs and minerals. It is meant to restore drained reserves of life force (ojas) and to preserve strength, stamina, and vitality, while stalling the course of aging. Chyawanprash is formulated by processing around 50 medicinal herbs and their extracts, including the prime ingredient, Amla (Indian gooseberry), which is the world's richest source of vitamin C. Chyawanprash preparation involves preparing a decoction of herbs, followed by dried extract preparation, subsequent mixture with honey, and addition of aromatic herb powders (namely clove, cardamom, and cinnamon) as standard. The finished product has a fruit jam-like consistency, and a sweet, sour, and spicy flavor. Scientific exploration of CP is warranted to understand its therapeutic efficacy. Scattered information exploring the therapeutic potential of CP is available, and there is a need to assemble it. Thus, an effort was made to compile the scattered information from ancient Ayurvedic texts and treatises, along with ethnobotanical, ethnopharmacological, and scientifically validated literature, that highlight the role of CP in therapeutics. Citations relevant to the topic were screened.

Two pairs of enantiomeric propylated flavonoids and a new lignan from the aerial parts of Abrus precatorius

Two pairs of novel enantiomeric flavonoids (1a, 1b and 2a, 2b), along with one new lignan (3), were isolated from the aerial parts of Abrus precatorius. All of these enantiomeric flavonoids featured an unprecedented propylated flavonoid skeleton representing a new family of flavonoid, and the new lignan was found to have an attractive arachidate ester side chain. Their structures were extensively elucidated by means of detailed NMR and mass spectroscopic analysis. Moreover, biological evaluation of antibacterial activity for these compounds against Bacillus cereus and Escherichia coli were conducted.

Antibacterial activity of flavonoids and their structure-activity relationship: An update review

Based on World Health Organization reports, resistance of bacteria to well-known antibiotics is a major global health challenge now and in the future. Different strategies have been proposed to tackle this problem including inhibition of multidrug resistance pumps and biofilm formation in bacteria and development of new antibiotics with novel mechanism of action. Flavonoids are a large class of natural compounds, have been extensively studied for their antibacterial activity, and more than 150 articles have been published on this topic since 2005. Over the past decade, some promising results were obtained with the antibacterial activity of flavonoids. In some cases, flavonoids (especially chalcones) showed up to sixfold stronger antibacterial activities than standard drugs in the market. Some synthetic derivatives of flavonoids also exhibited remarkable antibacterial activities with 20- to 80-fold more potent activity than the standard drug against multidrug-resistant Gram-negative and Gram-positive bacteria (including Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). This review summarizes the ever changing information on antibacterial activity of flavonoids since 2005, with a special focus on the structure-activity relationship and mechanisms of actions of this broad class of natural compounds.

Improving the Concentrations of the Active Components in the Herbal Tea Ingredient, Uraria crinita: The Effect of Post-harvest Oven-drying Processing

Uraria crinita is widely used as a popular folk drink; however, little is known about how the post-harvest operations affect the chemical composition and bioactivity of UC. We assessed three drying methods (Oven-drying, Air-drying, Sun-drying), as well as the Oven-drying temperature using metabolomics approaches and bioactivity assays. The samples processed at 40 degree show a greater effect on the levels of estrogen receptor-alpha activity and nuclear factor erythroid 2-related factor 2 activity, anti-oxidative activity, and cyclooxygenase-2 inhibition compared with the other samples. A multivariate analysis showed a clear separation between the 40 degree Oven-dried samples and the other samples, which is consistent with the results of bioactivity assay. These results are ascribed to at least two-fold increase in the concentrations of flavonoids, spatholosineside A and triterpenoids in the oven-dried samples compared with the other groups. The proposed Oven-drying method at 40 degree results in an improved quality of UC.

Wound healing and antimicrobial activity of two classical formulations of Laghupanchamula in rats

Background:

Wounds affect a large number of patients and seriously reduce the quality of life. The wound as a medical problem was first discussed by Maharshi Agnivesha in Agnivesha Samhita (later known as Charaka Samhita) as Vrana. Laghupanchamula denotes a combination of the roots of five herbs. However, in Ayurvedic classics, besides four common herbs viz. Kantakari, Brihati, Shalaparni and Prinshniparni, the fifth one is either Gokshura (LPG) or Eranda (LPE), and both formulations have been documented to have wound healing (Vrana) activity.

Objective:

The present study was undertaken to determine the in vivo wound healing activity and in vitro antimicrobial activity of 50% ethanolic extract of Laghupanchamula containing Gokshura (LPGE) and Laghupanchamula containing Eranda (LPEE) in rats with acute toxicity in mice.

Materials and Methods:

LPGE and LPEE (1000 mg/kg) was administered orally, once daily for 10 days (incision wound model) or for 24 days (excision wound model) in rats. LPGE and LPEE was studied for its in vitro antimicrobial and in vivo wound breaking strength (WBS) (incision model) and rate of contraction, period of epithelization and histology of skin (excision model).

Results and Conclusion:

LPGE and LPEE showed antimicrobial activity against skin pathogens, enhanced WBS, rate of contraction, skin collagen tissue formation and early epithelization period with low scar area indicating enhanced healing with histological evidence of more collagen formation in skin tissues. LPGE and LPEE also showed anti-bacterial activity and seemed to be safe, and use of both formulations in Laghupanchamula for their wound healing and anti-microbial activities is thus authenticated.

Analgesic and hypnotic activities of Laghupanchamula: A preclinical study

Background:

In Ayurvedic classics, two types of Laghupanchamula -five plant roots (LP) have been mentioned containing four common plants viz. Kantakari, Brihati, Shalaparni, and Prinshniparni and the fifth plant is either Gokshura (LPG) or Eranda (LPE). LP has been documented to have Shothahara (anti-inflammatory), Shulanashka (analgesic), Jvarahara (antipyretic), and Rasayana (rejuvenator) activities.

Aim:

To evaluate the acute toxicity (in mice), analgesic and hypnotic activity (in rats) of 50% ethanolic extract of LPG (LPGE) and LPE (LPEE).

Materials and Methods:

LPEG and LPEE were prepared separately by using 50% ethanol following the standard procedures. A graded dose (250, 500 and 1000 mg/kg) response study for both LPEE and LPGE was carried out for analgesic activity against rat tail flick response which indicated 500 mg/kg as the optimal effective analgesic dose. Hence, 500 mg/kg dose of LPEE and LPGE was used for hot plate test and acetic acid induced writhing model in analgesic activity and for evaluation of hypnotic activity.

Results:

Both the extracts did not produce any acute toxicity in mice at single oral dose of 2.0 g/kg. Both LPGE and LPEE (250, 500, and 1000 mg/kg) showed dose-dependent elevation in pain threshold and peak analgesic effect at 60 min as evidenced by increased latency period in tail-flick method by 25.1-62.4% and 38.2-79.0% respectively. LPGE and LPEE (500 mg/kg) increased reaction time in hot-plate test at peak 60 min analgesic effect by 63.2 and 85.8% and reduction in the number of acetic acid-induced writhes by 55.9 and 65.8% respectively. Both potentiated pentobarbitone-induced hypnosis as indicated by increased duration of sleep in treated rats.

Conclusion:

The analgesic and hypnotic effects of LP formulations authenticate their uses in Ayurvedic system of Medicine for painful conditions.

A new sesquilignan glucoside from Uraria sinensis

A new sesquilignan glucoside, urariasinoside A (1), together with eight known compounds, including two lignans, a sesquilignan, a dilignan, and four flavonoid derivatives were isolated from the aerial parts of Uraria sinensis. Their structures were determined on the basis of extensive spectroscopic analyses and comparison with literature data. Compound 1 was evaluated for in vitro cytotoxicity activity against HL-60, SMMC-7721, A549, MCF-7, SW480, and BEAS-2B cell lines.

Deglycosylation of isoflavones in isoflavone-rich soy germ flour by Aspergillus oryzae KACC 40247

Aspergillus oryzae KACC 40247 was selected as an efficient daidzein-producing fungus from strains of the genus Aspergillus by using 5% (w/v) soy germ flour (SGF) as an isoflavone-glycoside-rich medium. The culture conditions, including SGF concentration, agitation speed, initial pH, temperature, and time, were optimized as follows: 7% (w/v) SGF, initial pH 6.0, 33 °C, 300 rpm, and 24 h in a 100 mL baffled flask. The determined amount of isoflavone aglycons in SGF using 50% ethyl acetate was the highest among the solvent systems tested and it was 3.7-fold higher than that using 70% methanol. Under the optimized conditions, the content and concentration of daidzein were 134 mg/g of SGF and 9.4 g/L, respectively, with a productivity of 391 ± 2.8 mg/L/h, and those of isoflavone aglycons were 165 mg/g of SGF and 11.5 g/L, respectively, with a productivity of 479 mg/L/h. Optimization of culture conditions increased the content, concentration, and productivity of isoflavone aglycons by 3.1-, 3.0-, and 3.7-fold, respectively. To our knowledge, this is the highest production of isoflavone aglycons reported to date.

A new plant-derived antibacterial is an inhibitor of efflux pumps in Staphylococcus aureus

An in-depth evaluation was undertaken of a new antibacterial natural product (1) recently isolated and characterised from the plant Hypericum olympicum L. cf. uniflorum. Minimum inhibitory concentrations (MICs) were determined for a panel of bacteria, including: meticillin-resistant and -susceptible strains of Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus; vancomycin-resistant and -susceptible Enterococcus faecalis and Enterococcus faecium; penicillin-resistant and -susceptible Streptococcus pneumoniae; group A streptococci (Streptococcus pyogenes); and Clostridium difficile. MICs were 2-8 mg/L for most staphylococci and all enterococci, but were ≥16 mg/L for S. haemolyticus and were >32 mg/L for all species in the presence of blood. Compound 1 was also tested against Gram-negative bacteria, including Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica serovar Typhimurium but was inactive. The MIC for Mycobacterium bovis BCG was 60 mg/L, and compound 1 inhibited the ATP-dependent Mycobacterium tuberculosis MurE ligase [50% inhibitory concentration (IC(50)) = 75 μM]. In a radiometric accumulation assay with a strain of S. aureus overexpressing the NorA multidrug efflux pump, the presence of compound 1 increased accumulation of (14)C-enoxacin in a concentration-dependent manner, implying inhibition of efflux. Only moderate cytotoxicity was observed, with IC50 values of 12.5, 10.5 and 8.9 μM against human breast, lung and fibroblast cell lines, respectively, highlighting the potential value of this chemotype as a new antibacterial agent and efflux pump inhibitor.

Cytotoxic flavanes from Uraria clarkei

Two new flavanes, (2R)-4'-hydroxy-2',5,7-trimethoxyflavane (1) and (2R,4R)-2',4'-dihydroxy-5,7-dimethoxyflavan-4-ol (2), were isolated from Uraria clarkei, together with two known compounds 5,7-dimethoxy-4'-hydroxyflavan (3) and 5,7,4'-trimethoxyflavan (4). The structures of the new flavanes were characterized by analyses of the MS, IR, UV, CD, 1D, and 2D NMR data. Cytotoxicity test suggested that compounds 1-4 possessed slight activity against K-562 and Hela cell lines, with the IC50 values ranging from 26.6 to 56.3 μM.

Anti-inflammatory activity of two classical formulations of Laghupanchamula in rats

Background:

Laghupanchamula denotes combinations of roots of five herbs. However, in Ayurvedic classics besides four common herbs viz. Kantakari, Brihati, Shaliparni, and Prinshniparni, the fifth one is either Gokshura (Laghupanchamula with Gokshura LPG) or Eranda (Laghupanchamula with Eranda LPE), and both formulations have been documented to have shothahara (anti-inflammatory) action.

Objectives:

The present study was undertaken to compare the anti-inflammatory activity of 50% ethanolic extract of LPG (LPGE) and LPE (LPEE) in rats and safety in mice.

Materials and Methods:

LPGE and LPEE were given orally, administered either just before or 60 min before experiment on mice and for 7 days to rats. Paw edema was induced by carrageenan (acute) and formalin (sub-acute), whereas granuloma pouch (sub-acute) was induced by turpentine in rats.

Results:

Both LPGE and LPEE (1.0 g/kg) at 3 h after their administration showed inhibition of formalin-induced paw edema by 46.2% and 44.3% (P < 0.001) and carrageenan-induced paw edema by 53.9% and 60.4% (P < 0.001), respectively. After 7 days of treatment, both LPGE and LPEE showed 26.3% (P < 0.01) and 32.5% (P < 0.05) inhibition, respectively, against formalin-induced paw edema, and reduced weight of turpentine-induced granuloma pouch by 42.8% and 36.1% (P < 0.001), and volume of exudates by 31.2% and 36.2% (P < 0.001), respectively. No acute toxicity was observed in mice even with a 10.0-g/kg dose of both extracts.

Conclusion:

LPGE and LPEE significantly reduced acute and sub-acute inflammation, and showed effective and similar anti-inflammatory activity. They seemed to be safe, and use of both formulations in the Laghupanchamula for their anti-inflammatory activity is, thus, authenticated.

Structure pre-requisites for isoflavones as effective antibacterial agents

Recent reports reveal that there is increasing incidence of infections of multidrug-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Flavonoids and related compounds have been shown to possess potent antimicrobial activities. Most of the flavonoids are considered as constitutive antimicrobial substances recently termed as “Phytoanticipins,” especially those belonging to prenylated flavonoids and isoflavones. The current review highlights the structure prerequisites for isoflavones as antibacterial agents. Structure–activity relationship (SAR) conclusions have been drawn by comparing the reported minimum inhibitory concentration values for the various isoflavones against S. aureus and MRSA. There exists a significant co-relationship between the presence of certain functional groups (prenyl group, phenolic hydroxyl) at particular positions and antibacterial activity of the compounds. These trends have been postulated with a view of assisting better drug designing of future next-generation antiinfectives, particularly against the bothersome multidrug-resistant microbes. The SAR of these isoflavones has also proved to be a basis to explore the mechanism of antibacterial action. Thus, the study would prove extremely useful to synthesize antibacterial isoflavones in future, which would eventually be beneficial for optimizing the lead molecule for the antibacterial action

Catalytic asymmetric alkylation of substituted isoflavanones

The asymmetric alkylation of isoflavanones (3-aryl-chroman-4-ones) and protected 3-phenyl-2,3-dihydroquinolin-4(1H)-ones catalyzed by a novel cinchonidine-derived phase transfer catalyst E is reported. This functionalization occurs at the unactivated C3 methine to afford novel products that can easily be functionalized to generate more complex fused ring systems. The process accommodates a variety of isoflavanones and activated electrophiles and installs a stereogenic quaternary center in high yield and with good-to-excellent selectivity. Isoflavanones are a privileged class of natural products with a broad spectrum of biological activities including insecticidal, antimicrobial, antibacterial, estrogenic, antitumor, and anti-HIV activity. (1) Isoflavanones are also precursors for more complex natural products such as pterocarpans and rotenones. (1) Given their therapeutic promise, selective strategies to access new classes of isoflavanones and related structures has high value. (2) The functionalization of the C3 position could promote beneficial interactions with biological targets of interest. Specifically, an alkylation at C3 can rapidly access new members of the general class of biologically active homoisoflavanones. (3).