Estrogenic Activity of Derris scandens Stem Extract and its Major Compounds Using MCF-7 Cell Proliferation Assay and Estrogen-Related Gene Expression.

Derris scandens, which contains isoflavones and prenylated derivatives, has analgesic and anti-inflammatory properties and is an ingredient in traditional Thai medicine for perimenopause and menopause. However, the estrogenic activity of D. scandens has not yet been explored. Therefore, this study aimed to examine the estrogenic activity of the stem extract of D. scandens and its isoflavone derivatives. In this study, we conducted a proliferation assay in MCF-7 cells, and used quantitative reverse transcription polymerase chain reaction to assess gene expression. We found that the relative cell proliferation of the compounds (1 µM) was ranked in the following order as compared to 0.1 nM 17ß-estradiol (100%): genistein (97.84%) > derrisisoflavone A (83.17%) > genistein-7-O-[α-rhamnopyranosyl-(1 → 6)-glucopyranoside] (69.55%) > 6,8-diprenylgenistein (51.91%) > lupalbigenin (18.72%). Furthermore, cotreatment with 1 µM lupalbigenin and 0.1 nM 17ß-estradiol was performed, which decreased cell proliferation to 80.38%. In vitro results suggest that lupalbigenin has an estrogen-antagonistic effect. At a dose of 1 µM, genistein had the strongest efficacy in increasing the expression of human estrogen receptor ß by 4.0-fold compared to the control. Furthermore, genistein-7-O-[α-rhamnopyranosyl-(1 → 6)]-ß-glucopyranoside augmented the gene expression of human estrogen receptor α and human estrogen receptor ß by 1.5- and 3.4-fold, respectively. Prenylated derivatives of genistein (derrisisoflavone A, 6,8-diprenylgenistein, and lupalbigenin) significantly suppressed the gene expression of the human androgen receptor. The administration of the crude extract at 10 µg/mL significantly suppressed human androgen receptor (0.6-fold) and transmembrane protease serine 2 (0.1-fold) expression but did not significantly affect human estrogen receptor α and human estrogen receptor ß gene expression. This herbal medicine may be safe for estrogen-exposed breast cancer patients.

Identification of Major Bioactive Anti-inflammatory Compounds of Derris scandens Stem Using RAW 264.7 Cells and HPLC-UV Analysis.

Derris scandens (DS) is widely recognized for its therapeutic properties, specifically its analgesic effects, which significantly alleviate muscle pain. The chemical constituents of DS stem include various isoflavone derivatives. However, there is currently a lack of specified anti-inflammatory chemical markers and analytical methods for quality control. The present study aimed to evaluate the anti-inflammatory activity of DS and its constituents using the RAW 264.7 cell model. The expression of inflammatory genes such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and 5-lipoxygenase (5-LOX) was examined using quantitative RT-PCR. An high-performance liquid chromatography with a UV detection method was developed to quantitatively analyze genistein-7-O-[α-rhamnopyranosyl-(1 → 6)]-ß-glucopyranoside, genistein, derrisisoflavone A, lupalbigenin, and 6,8-diprenylgenistein in DS stem. The developed HPLC-UV method demonstrated high sensitivity with limits of detection and quantification ranging from 0.01 to 0.06 µg/mL and 0.03 to 0.18 µg/mL, respectively. The accuracy of the method ranged from 93.3 to 109.6%. Furthermore, the repeatability and reproducibility of the method were suitable, as indicated by the relative standard deviations of ≤ 3.02% and ≤ 6.22%, respectively. The DS extract notably inhibited NO production, exhibiting effects comparable to those of 500 µM diclofenac, and substantially suppressed the expression of iNOS, COX-2, IL-6, and 5-LOX of lipopolysaccharide (LPS)-induced genes. As to the pure isoflavone derivatives, the order of NO production inhibition was found to be genistein > lupalbigenin > derrisisoflavone A > 6,8-diprenylgenistein > genistein-7-O-[α-rhamnopyranosyl-(1 → 6)]-ß-glucopyranoside. Genistein, derrisisoflavone A, and 6,8-diprenylgenistein significantly suppressed the upregulation of all LPS-induced genes. Consequently, these compounds are recommended as anti-inflammatory markers for the quantitative chemical analysis of DS.

Study on Chemical Components from Derris taiwaniana and Their Lung Epithelial Cell Protect Effects.

The ethanol extract of roots of Derris taiwaniana gave two undescribed compounds, 3,3'-dimethoxy-5'-hydroxystilbene-4-O-ß-apiofuranosyl-(1→6)-ß-D-glucopyranoside (1) and 4',5-dihydroxy-3'-methoxyisoflavone-7-O-ß-apiofuranosyl-(1→6)-ß-D-glucopyranoside (2), along with thirty known components. Among them, compounds 14, 16-17, 23, 26-32 were isolated from this genus for the first time. Their structures were established based on physico-chemical properties and spectroscopic data, the lung epithelial cell protective effects were evaluated using NNK-induced MLE-12 cells. Among them, 2α,3α-epoxy-5,7,3',4'-tetrahydroxyflavan-(4ß-8-catechin) (30) showed the best significant protective effect, speculated to be the key component of D. taiwaniana that plays a protective role in lung epithelial cells.

Inhibitory Effects of Thermolysis Transformation Products of Rotenone on Nitric Oxide Production.

Rotenone, isolated from Derris, Lonchocarpus, and Tephrosia from the family Fabaceae, has been shown to have a variety of biological properties and is used in various agricultural industries as a potent biopesticide. However, recent reports have demonstrated that rotenone has the potential to cause several adverse effects such as a neurodegenerative disease. This study aimed to induce thermolysis of the biopesticide rotenone and enhance the functionality of the degraded products. Rotenone (1) was degraded after autoclaving for 12 h, and the thermolytic reactants showed enhanced anti-inflammatory capacity against nitric oxide (NO) production. The structures of the newly modified products were spectroscopically determined. The thermal reaction products included various isoflavonoid derivatives 2-6, whose structures were characterized as being produced via chemical reactions in rotenone at the C-12 positions. Among the degraded products, (-)-tubaic acid (6) exhibited significantly improved anti-inflammatory effects compared to the original rotenone. Quantitative LC-MS analysis of the major thermolysis products generated in Derris extract containing rotenone was performed using isolate 2-5 purified from autoclaved rotenone. These results suggest that the thermal transformation of rotenone can improve the functionality of anti-inflammatory agents.

Derrisrobustones A-D, isoflavones from the twig extract of Derris robusta (DC.) Benth. and their α-glucosidase inhibitory activity.

Three previously undescribed isoflavones, derrisrobustones A-C, and a previously undescribed natural isoflavone, derrisrobustone D, along with eight known isoflavones, were isolated from the twig extract of Derris robusta (DC.) Benth. All structures were identified by extensive spectroscopic analysis. Derrisrobustones A-C were obtained as scalemic mixtures and were resolved by chiral HPLC. The (1″R, 2″R) absolute configuration of (+)-derrisrobustone B was established by single-crystal X-ray crystallography using Cu Kα radiation. The absolute configurations of derrisrobustones A and C were determined by analysis of experimental and calculated ECD data. All compounds were evaluated for their α-glucosidase inhibitory activity. Of these, derrubone displayed the best α-glucosidase inhibitory activity with an IC50 value of 64.2 µM.

Susceptibility of Aedes albopictus Larvae to the Larvicidal Activity of Three Types of Derris elliptica Extract.

<b>Background and Objective:</b> The methanol, ethyl acetate and n-hexane extracts of <i>D. elliptica</i> root have high larvicidal activity against <i>Aedes aegypti</i> larvae, the primary vector of dengue but have not been understood their potential against <i>Ae. albopictus</i> larvae, the secondary vector of dengue that also transmits Chikungunya and Zika viruses. This <i>in vitro</i> study aims to understand the larvicidal activity of the 3 extract types of <i>D. elliptica </i>root against <i>Ae. albopictus</i> larvae. <b>Materials and Methods:</b> The tuba root extract types were obtained from the sequential extraction process with 3 steps of liquid-liquid partition as described in the previous report. Six concentrations were occupied in this experiment ranging of 0.5, 1.0, 2.0, 4.0, 10.0 and 15.0 mg L¹ each concentration was 5 times replicated and placed in 250 mL plastic cups. As many as 20 of 3rd instar larvae of <i>Ae. albopictus</i> were subjected in each treatment cup and larval mortality was observed after 24 and 48 hrs of exposure. <b>Results:</b> Larval mortality rates based on concentration range of 13.75-97.00 and 43,75-100%, 14.00-44.00, 34.00-90.00%, 12.00-47.00 and 28.00-88.00%, with the LC₅₀ after 24 and 48 hrs of exposure were 2.925 and 0.414, 16.184, 2.900, 15.789 and 4.380 mg L¹, respectively for methanol, ethyl acetate and n-hexane extracts. <b>Conclusion:</b> The methanol, ethyl acetate and n-hexane extract of tuba root have high larvicidal activity against <i>Ae. albopictus</i> larvae. Further study on prototype formulation of larvicide and elucidation of the specific phytochemical compounds of the extracts were necessarily conducted.

A new anti-austerity agent, 4'-O-methylgrynullarin from Derris scandens induces PANC-1 human pancreatic cancer cell death under nutrition starvation via inhibition of Akt/mTOR pathway.

An ethanolic extract of Derris scandens flowers showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived condition, with a PC50 value of 0.7 µg/mL. Phytochemical investigation of this active extract led to the isolation of four prenylated isoflavones (1-4) including a new compound named 4'-O-methylgrynullarin (1). The structure elucidation of the new compound was achieved by HRFABMS and NMR spectroscopic analysis. The isolated compounds exhibited potent anti-austerity activity against four different human pancreatic cancer cell lines under nutrient-deprived conditions. The new compound 4'-O-methylgrynullarin (1) was also found to inhibit PANC-1 cell migration and colony formation under nutrient-rich condition. Mechanistically, compound 1 inhibited key survival proteins in the Akt/mTOR signaling pathway. Therefore, 4'-O-methylgrynullarin (1) can be considered as a potential lead compound for the anticancer drug development based on the anti-austerity strategy.

α-Glucosidase inhibitory, antibacterial, and antioxidant activities of natural substances from the wood of Derris reticulata Craib.

Derris reticulata (Leguminosae-Papilionoideae) has been used for the treatment of diabetes in Thai folk remedies. The phytochemical investigation of the wood of D. reticulata revealed the isolation of two new pyranoflavanones, 4'-methoxydereticulatin (1) and 2'''-hydroxy,3'''-ethoxylupinifolin (2), along with five known compounds namely lupinifolin (3), 2''',3'''-dihydroxylupinifolin (4), genistein (5), lupeol (6), and ß-sitosterol (7). Compounds 1-4 were selected for antibacterial assay using broth microdilution method, and displayed good activity against four out of five tested pathogenic bacterial strains, with MIC values ranging from 0.78 to 128 µg/mL. The result from spectrophotometric assay of α-glucosidase inhibition showed that 5 exhibited promising α-glucosidase inhibitory activity, compared with the positive control acarbose. Additionally, it was found that compounds 4 and 5 showed moderate DPPH and NO radicals scavenging activity. Modeling studies were also performed to suggest the interaction modes of compounds 3-5 in the α-glucosidase enzyme active site.

Therapeutic Potential of Genus Pongamia and Derris: Phytochemical and Bioactivity.

Genus Pongamia and Derris belong to the Leguminosae family and are reported synonymously in literature. Although many compounds have been isolated from different plant parts but seed oil is known to produce non-edible medicinally important furanoflavonoids. The seed oil, commonly known as Karanj oil in Ayurvedic and Siddha traditional systems of medicine, is reported for the treatment of various skin infections and psoriasis. Several phytopharmacological investigations have proved the medicinal potential of furanoflavonoids in the skin and other disorders. Not only furanoflavonoids but several other important phenolic constituents such as chalcones, dibenzoylmethanes, aurones, isoflavones, flavanone dihydroflavonol, flavans, pterocarpans, rotenoids, coumarins, coumestans, stilbenoids and peltygynoids and their glycosides have been reported for different biological activities including antihyperglycemic, anti-inflammatory, anticancer, insecticidal, anti-alzheimer's, gastro protective, antifungal, antibacterial, etc. In the present review, the phytochemistry and pharmacological activities of the genera Pongamia and Derris have been summarized.

Evaluation of Toxicity in Four Extract Types of Tuba Root against Dengue Vector, Aedes aegypti (Diptera: Culicidae) Larvae.

BACKGROUND AND OBJECTIVE: Since the Dengue virus spreads rapidly and the vector becomes resistant to insecticides and larvicides, exploration of new compounds that overcome resistance problems, are easily degraded and do not lead to bioaccumulation, is needed. This study evaluated four extract types of Derris elliptica represented the polar, semi-polar and nonpolar extract against the 3rd-instar larvae of Ae. aegypti and determined the effective concentration among the extracts. MATERIALS AND METHODS: The crude extract was obtained from the maceration of root powder of the plant with methanol and subsequently evaporated. The crude extract was diluted in distilled water and partitioned sequentially with ethyl-acetate, n-hexane and water to obtain their fractions. All the fractions were evaporated to obtain their extract types. Initial bioassay test of the extracts with concentration ranges of 50, 100, 500 and 1,000 mg L-1 against Ae. aegypti larvae and resulted in 86-100% larval mortality rates at concentrations of 50 and 100 mg L-1, except for water extract. The lower concentration range of 3, 5, 10, 25, 50 and 100 mg L-1 of three extract types were tested. RESULTS: Larval mortality rates of 18.4-100, 1.6-99.2 and 0.8-98.4% with LC50 of 4.088, 14.066 and 21.063 mg L-1, respectively for n-hexane, methanol and ethyl-acetate. FTIR analysis indicated nine lead compounds in which rotenone and ceramides were observed in all extract types. CONCLUSION: The n-hexane extract showed the highest larvicidal toxicity and its specific compounds are necessarily isolated to obtain pure bioactive ingredients.

Characterization of a new natural cellulosic fiber extracted from Derris scandens stem.

The present study aims to identify a potential substitute for the harmful synthetic fibers in the field of polymer composites. With this objective, a comprehensive characterization of Derris scandens stem fibers (DSSFs) was carried out. The presence of high strength gelatinous fibers with a traditional hierarchical cell structure was found in the anatomical study. The chemical compositional analysis estimated the cellulose, hemicellulose, and lignin contents of 63.3 wt%, 11.6 wt%, and 15.3 wt%, respectively. Further analysis with XRD confirmed the presence of crystalline cellulose having a size of 11.92 nm with a crystallinity index of 58.15%. SEM and AFM studies show that these fibers are porous, and the average roughness is 105.95 nm. Single fiber tensile tests revealed that the DSSFs exhibited the mean Young's modulus and tensile strength of 13.54 GPa and 633.87 MPa respectively. Furthermore, the extracted fibers were found to be thermally stable up to 230 °C, as confirmed by thermogravimetric analysis. The fibers extracted from the stem of medicinal plant Derris scandens have the properties comparable to that of existing natural fibers, thus, suggesting it to use as a highly promising reinforcing agent alternative to synthetic fibers in polymer matrix composites.

Two new diprenylated flavanones from Derris laxiflora Benth.

Phytochemical reinvestigation on the whole plants of Derris laxiflora Benth. afforded two new diprenylated flavanones, derriflavanones B and C (1-2), together with thirty-two known compounds, including sixteen flavonoids (3-18), eleven aromatic compounds (19-29), and five chlorophylls (30-34). All known compounds were first isolated from this plant. The structures of these compounds were determined by analysis of the NMR spectroscopy, mass data, IR spectra, UV spectra, optical rotation and by comparison with literature data.

Development of monoclonal antibody-based enzyme-linked immunosorbent assay for quantitative quality control of Derris scandens (Roxb.) Benth.

Derris scandens (Roxb.) Benth. is a medicinal plant used for treatment of musculoskeletal pain in Thai traditional medicines. Its stem contains active compound genistein-7-O-[α-rhamnopyranosyl-(1 to 6)-ß-glucopyranoside] (GTG) which is used as a biomarker for standardization of D. scandens extracts. As an alternative for rapid quantitation of GTG, a monoclonal antibody against GTG was prepared and applied for an indirect competitive enzyme-linked immunosorbent assay (ELISA) to determine GTG in plants and herbal products. The established method provided a quantification range of 0.31-10 µg/mL with a limit of detection of 0.29 µg/mL. The assay was validated for precision and accuracy by intra- and interassay variation analyses, recovery test, and comparison analysis between the amounts of GTG determined by ELISA and HPLC. The results exhibited that the developed ELISA is sensitive and effective for determination of GTG in D. scandens plant materials and herbal products.

Anticariogenic Activities of Derris reticulata Ethanolic Stem Extract Against Streptococcus mutans.

BACKGROUND AND OBJECTIVE: Streptococcus mutans is a dominant causative pathogen of dental caries, which is a major oral health problem affecting million people worldwide. Derris reticulata is a medicinal plant possessing antimicrobial activity against several Gram-positive pathogenic bacteria. None the less, its effects on growth and cariogenic properties of S. mutans has not been clearly established. This study aimed to investigate the antibacterial and anti cariogenic activities of the D. reticulata ethanolic stem extract. MATERIALS AND METHODS: The TLC analysis was performed to authenticate the D. reticulata sample. Minimum inhibition concentration and minimum bactericidal concentration were determined by using broth dilution and drop plate methods, respectively. Sucrose dependent and sucrose independent-adherences, biofilm formation and glycolytic pH drop assays were performed to evaluate the anticariogenic activity. RESULTS: The ethanolic stem extract of D. reticulata possessed the antibacterial activity against S. mutans with the MIC and MBC of 0.875±0.250 and 1.750±0.500 mg mL-1, respectively. The extract at the lower concentrations of sub-MIC also had significant inhibitory actions against the cariogenic properties of S. mutans, including surface adherence, biofilm formation and glycolytic acid production. CONCLUSION: The D. reticulata stem extract had a substantial anticariogenic activities and thus potentially be developed as an oral health care product for dental caries prevention in the near future.

Phosphodiesterase 5 Inhibitors from Derris scandens.

Phosphodiesterase 5 inhibitors have been used as a first-line medicine for the treatment of erectile dysfunction. In the search for new phosphodiesterase 5 inhibitors from natural sources, we found that the 95% ethanol extract of Derris scandens stem showed phosphodiesterase 5 inhibitory activity with an IC50 value of about 7 µg/mL. Seven isoflavones and a coumarin constituent isolated from this plant were investigated for phosphodiesterase 5 inhibitory activity. The results showed that osajin (8: ), 4',5,7-trihydroxybiprenylisoflavone (4: ), and derrisisoflavone A (2: ) had the ability to inhibit phosphodiesterase 5 with IC50 values of 4, 8, and 9 µM, respectively. These compounds exhibited selectivity on phosphodiesterase 5 over phosphodiesterase 1, however, the selectivity on phosphodiesterase 5 over phosphodiesterase 6 was low. In order to quantitatively determine these bioactive constituents in D. scandens extract, LC-QTOF-MS method has been developed and validated. The limit of quantitation values in the range of 0.1 - 5 µg/mL were obtained. The assay showed satisfactory precision and accuracy. The results from our method showed that the 95% ethanol extract of D. scandens stem was comprised of all eight compounds, with derrisisoflavone A (2: ) and lupalbigenin (3: ) presenting as the major constituents.

Anti-Angiogenic Activity of Rotenoids from the Stems of Derris trifoliata.

The plants in the genus Derris have proven to be a rich source of rotenoids, of which cytotoxic effect against cancer cells seem to be pronounced. However, their effect on angiogenesis playing a crucial role in both cancer growth and metastasis has been seldom investigated. This study aimed at investigating the effect of the eight rotenoids (1: -8: ) isolated from Derris trifoliata stems on three cancer cells and angiogenesis. Among them, 12a-hydroxyrotenone (2: ) exhibited potent inhibition on both cell growth and migration of HCT116 colon cancer cells. Further, anti-angiogenic assay in an ex vivo model was carried out to determine the effect of the isolated rotenoids on angiogenesis. Results revealed that 12a-hydroxyrotenone (2: ) displayed the most potent suppression of microvessel sprouting. The in vitro assay on human umbilical vein endothelial cells was performed to determine whether compound 2: elicits anti-angiogenic effect and its effect was found to occur via suppression of endothelial cells proliferation and tube formation, but not endothelial cells migration. This study provides the first evidence that compound 2: could potently inhibit HCT116 cancer migration and anti-angiogenic activity, demonstrating that 2: might be a potential agent or a lead compound for cancer therapy.

Stereocontrolled Semisyntheses of Elliptone and 12aß-Hydroxyelliptone.

Operationally simple, stereocontrolled semisyntheses of the anticancer rotenoids elliptone and 12aß-hydroxyelliptone, isolated from Derris elliptica and Derris trifoliata, respectively, are described. Inspired by the work of Singhal, elliptone was prepared from rotenone via a dihydroxylation-oxidative cleavage, chemoselective Baeyer-Villiger oxidation, and acid-catalyzed elimination sequence. Elaboration of elliptone to 12aß-hydroxyelliptone was achieved via a diastereoselective chromium-mediated Étard-like hydroxylation. The semisynthesis of elliptone constitutes an improvement over previous methods in terms of safety, scalability, and yield, while the first synthesis of 12aß-hydroxyelliptone is also described.

Photo-induced and phytomediated synthesis of silver nanoparticles using Derris trifoliata leaf extract and its larvicidal activity against Aedes aegypti.

Due to the increased development of resistance of vectors against synthetic insecticides and chemical drugs, plant based insecticides serve as promising biocontrol agents for effective vector control. Green approach for the synthesis of nanoparticles has been attained using environmentally safe, non-toxic plant extracts. The present study was aimed to investigate the potent larvicidal activity of silver nanoparticles (AgNPs) produced by Derris trifoliata leaf extract in relation to the various concentrations of methanol and chloroform extracts for 24h against 3rd and 4th instar larvae of Aedes aegypti. AgNPs were synthesized using D. trifoliata leaf extract as reducing and stabilizing agent. Synthesized AgNPs were characterized by UV-Vis spectroscopy, FTIR spectroscopy, SEM, EDX, XRD and HRTEM. The size of AgNPs as estimated from the full width at half-maximum of (200) peak of silver was 16.13nm, the average crystalline size of the synthesized AgNPs was approximately 20nm, which was correlated with the HRTEM results (20nm). SEM and TEM images have shown the formation of polydispersed nanoparticles with an average size of 20nm. The FTIR spectra of AgNPs exhibited prominent peaks at 2360.7, 1606.2, 1095.6 and 785.9cm-1. The spectral peak observed at 1606.2, assigned to stretching vibration (C=O) in carbonyl compounds characterized by the presence of major constituents of flavonoids and terpenoids. The results obtained in FTIR spectroscopy correlated with the GC-MS analysis of methanol and chloroform extracts and indicates the presence of phytosteroids, flavonoids and terpenoids. The highest larvicidal activity was observed for the synthesized AgNPs against the 3rd instar larvae with LC50 values of 5.87mg/l and LC90 of 12.11mg/l, while against 4th instar larvae these values were7.00 and17.76mg/l respectively. The chloroform extracts also showed increased larvicidal activity than methanol extracts against 3rd instar larvae (LC50=54.42mg/l, LC90=140.83mg/l) and 4th instar larvae (LC50=62.47mg/l, LC90=145.06mg/l) of A. aegypti. Besides, the synthesized AgNPs also exhibited potent antibacterial activity against certain food borne pathogens. These results infer that the biologically synthesized AgNPs and organic solvent extracts have the potential to be used as an excellent eco-friendly approach for vector control against A. aegypti.

New Sweet-Tasting Oleanane-Type Triterpenoid Saponins from "Tugancao" (Derris eriocarpa How).

With the aim to investigate the sweet-tasting compounds in Derris eriocarpa How (a substitute for licorice in "Zhuang" and "Dai" ethnopharmacy in Guangxi and Yunnan provinces of China) as well as to ascertain why the stem of D. eriocarpa can be used to substitute for licorice in the sweetness taste aspect, taste sensory-guided fractionation was conducted to isolate sweet constituents from the extract of D. eriocarpa. Four sweet-tasting triterpenoid saponins were obtained, including millettiasaponin A (1) and three new saponins named derrisaponins A-C (2-4). The sweetness potency was evaluated by a human sensory panel test. The sweetness intensities of compounds 1-4 were determined to be approximately 150, 80, 2, and 0.5 times relative to sucrose at the concentration of 1%, respectively, of which compounds 1 and 2, with a free carboxyl group at the C-30 position, showed more potent sweetness intensity. In addition, compounds 1 and 2 showed no acute toxic activity at doses of 250 and 400 mg/kg of body weight, respectively, assessed through caudal vein injection to ICR mice. The contents of the sweetest compounds in stems were analyzed quantitatively as 352.80 mg/kg for compound 1 and 1887.60 mg/kg for compound 2 performed by ultra-performance liquid chromatography-tandem mass spectrometry.

Lupinifolin from Derris reticulata possesses bactericidal activity on Staphylococcus aureus by disrupting bacterial cell membrane.

In this study, lupinifolin, a prenylated flavonoid, was isolated from Derris reticulata stem, identified by NMR spectra and confirmed with mass spectrometry. Lupinifolin was freshly prepared by solubilizing in 0.1 N NaOH and immediately diluted in Müller-Hinton broth for antibacterial testing. The data showed that Gram-positive bacteria were more susceptible to lupinifolin than Gram-negative bacteria. Of four strains of Gram-positive bacteria tested, Staphylococcus aureus was the most susceptible. Using the two-fold microdilution method, it was found that lupinifolin possessed antimicrobial activity against S. aureus with minimum inhibitory concentration and minimum bactericidal concentration of 8 and 16 µg/ml, respectively, which is less potent than ampicillin. However, from the time-effect relationship, it was shown that lupinifolin had faster onset than ampicillin. The faster onset of lupinifolin was confirmed by scanning electron microscopy. To investigate the mechanism of action of lupinifolin, transmission electron microscopy (TEM) was performed to observe the ultrastructure of S. aureus. The TEM images showed that lupinifolin ruptured the bacterial cell membrane and cell wall. Due to its fast onset, it is suggested that the action of lupinifolin is likely to be the direct disruption of the cell membrane. This hypothesis was substantiated by the data from flow cytometry using DiOC2 as an indicator. The result showed that the red/green ratio which indicated bacterial membrane integrity was significantly decreased, similar to the known protonophore carbonyl cyanide 3-chlorophenylhydrazone. It is concluded that lupinifolin inhibits the growth of S. aureus by damaging the bacterial cytoplasmic membrane.