Antimicrobial and Antioxidant Properties of Four Lycopus Taxa and an Interaction Study of Their Major Compounds

The compositions of leaf infusions of three genotypes of Lycopus europaeus L. with origins in central Europe, namely L. europaeus A (LeuA), L. europaeus B (LeuB), and L. europaeus C (LeuC), and one genotype of L. exaltatus (Lex), were examined by LC-MS-DAD (Liquid Chromatography Mass Spectrometry and Diode Array Detection) analysis. This revealed the presence of thirteen compounds belonging to the groups of phenolic acids and flavonoids, with a predominance of rosmarinic acid (RA) and luteolin-7-O-glucuronide (LGlr). The antimicrobial activity of leaf infusions was tested on the collection strains of Gram-positive and Gram-negative bacteria, and on the clinical Staphylococcus aureus strains. We detected higher activity against Gram-positive bacteria, of which the most susceptible strains were those of Staphylococcus aureus, including methicillin-resistant and poly-resistant strains. Furthermore, we examined the antioxidant activity of leaf infusions using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) methods, and on NIH/3T3 cell lines using dichlorodihydrofluorescein diacetate (DCFH-DA). We also studied the mutual interactions between selected infusions, namely RA and/or LGlr. In the mixtures of leaf infusion and RA or LGlr, we observed slight synergism and a high dose reduction index in most cases. This leads to the beneficial dose reduction at a given antioxidant effect level in mixtures compared to the doses of the parts used alone. Therefore, our study draws attention to further applications of the Lycopus leaves as a valuable alternative source of natural antioxidants and as a promising topical antibacterial agent for medicinal use.

Lycopus lucidus Turcz. ex Benth. Attenuates free fatty acid-induced steatosis in HepG2 cells and non-alcoholic fatty liver disease in high-fat diet-induced obese mice

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is closely related to metabolic diseases such as obesity and insulin resistance.

PURPOSE

We studied whether an ethanol extract of Lycopus lucidus Turcz. ex Benth (LLE) exhibited effects on lipid metabolism in NAFLD.

STUDY DESIGN

An in vitro modelwas established by treatment of HepG2 cells with a 1 mM free fatty acid (FFA) mixture (oleic acid/palmitic acid, 2:1). C57BL/6 mice were fed a high-fat diet (HFD; 60 kcal% fat) for 14 weeks to induce obesity and were treated with or without LLE (100 or 200  mg/kg daily by oral gavage).

METHODS

HepG2 cells were exposed to 1 mM FFA, with or without LLE (250 - 1000  mg/ml). Intracellular lipid contents were measured by Oil Red O staining and a Nile Red assay. The body weight, relative liver weight, hepatic lipids, triglycerides (TGs), and total cholesterol (TC) were measured in the mice. Serum alanine aminotransferase (ALT), TG, TC, glucose, insulin, leptin, and tumor necrosis factor-alpha (TNF-α) levels were determined by biochemical or enzyme-linked immunosorbent assays. Histologic analysis was performed in the liver. Western blotting and quantitative real-time polymerase chain reaction were used to analyze the expression of key enzymes of hepatic lipid metabolism.

RESULTS

LLE significantly decreased the intracellular lipid accumulation in FFA-treated HepG2 cells. LLE not only remarkably decreased the expression of lipogenesis genes but also increased β-oxidation in FFA-induced HepG2 cells. In the in vivo study, LLE treatment significantly decreased the body weight, relative liver weight, serum ALT, TC, and low-density lipoprotein cholesterol, as well as the serum glucose, insulin, leptin, and TNF-α levels in HFD-fed mice. The hepatic TG and TC contents were significantly reduced in the LLE-treated groups. Western blot analysis showed that the expression of sterol-regulatory element-binding protein 1 decreased, while that of phosphorylated AMP-activated protein kinase and peroxisome proliferator-activated receptor α increased in the LLE-treated mice.

CONCLUSION

These results suggest that LLE may exert protective effects against NAFLD-related obesity and metabolic disease.

Identification of the NADPH Oxidase 4 Inhibiting Principle of Lycopus europaeus

NADPH oxidase 4 (Nox4) has recently been implicated as driving force in cellular senescence. Thus, there is growing interest to develop Nox4 inhibitors, which might be valuable agents for cosmeceutical applications. Alpine plants represent a valuable source for the identification of novel bioactive natural products with anti-ageing effects, especially substances that protect plants against UV radiation, which is also known to contribute to the ageing of human skin. Therefore, the aim of this study was to identify novel Nox4 inhibitors from alpine plants. Within an initial screening of extracts of alpine plants on their ability to inhibit Nox4 activity in HEK cells, the methanolic extract of the subaerial parts of Lycopus europaeus showed a strong inhibition of Nox4 (81% chemiluminescence quenching) and a simultaneously high cell viability (91% vitality). Rosmarinic acid was isolated and identified as the major compound in this bioactive extract. It showed a dose dependent inhibitory activity on Nox4 with an IC50 of 1 µM. Moreover, it also showed a significant inhibitory activity on Nox2 in the low micromolar range, whereas no inhibition of Nox5 was detected. Further investigations confirmed that the observed effects of rosmarinic acid on Nox2 and Nox4 are real inhibitory activities, and not due to ROS scavenging effects. Therefore, L. europaeus, which we demonstrated to be a good source of rosmarinic acid, has great potential for usage in cosmeceutical products with anti-ageing activity.

Pancreatic lipase and α-amylase inhibitory activities of plants used in Traditional Chinese Medicine (TCM)

To find new, plant based drugs for the treatment of obesity and/or diabetes mellitus type 2 through the inhibition of essential digestive enzymes, in vitro tests were carried out on selected plants or fungi with weight-reducing, blood glucose-reducing or related potential, used in Traditional Chinese Medicine (TCM). Aqueous and methanolic extracts of 32 Chinese herbal medicines were assayed for their in vitro inhibitory activity against pancreatic lipase (PL) and α-amylase (PA). PL activity was measured by using an enzymatic in vitro assay based on the hydrolysis kinetics of an oleate ester of 4-methylumbelliferone. For the determination of α-amylase activity an enzyme assay based on the hydrolytic cleavage of a modified starch derivative was used. Our findings have shown that the methanolic extract of Lycopus lucidus Turcz. var. hirtus Regel (Lamiaceae) was a very effective PL inhibitor (IC50: 88.3±4.1 μg/mL). A high anti-amylase activity showed the methanolic extract of Trichosanthes kirilowii Maxim. (Curcurbitaceae, IC50: 248.8±67.3 μg/mL). This work provides a priority list of interesting plants for further study with respect to the treatment of obesity and associated metabolic diseases.

Variation in nutritional compositions, antioxidant activity and microstructure of Lycopus lucidus Turcz. root at different harvest times

The objective of this study was to investigate the variation in nutritional compositions, antioxidant activity and microstructure of Lycopus lucidus Turcz. root at different harvest times. L. lucidus Turcz. roots, harvested from two sites (S1 and S2) at three different times (T1: 19-11-2013, T2: 22-12-2013 and T3: 27-01-2014), were analyzed for nutritional compositions, antioxidant activity by DPPH, FRAP and TEAC assays and microstructure. The results revealed that the protein content in L. lucidus Turcz. root first decreased and then increased to a maximum at T3. The reducing sugar content had no significant differences among the three harvest dates studied. The starch content decreased drastically along with an increase of crude fat content with the harvest time delayed. The major amino acids in L. lucidus Turcz. root were aspartic acid and glutamate and the highest total amino acid content was found for the root harvested at T3. The most common element in L. lucidus Turcz. root was detected to be potassium followed by calcium, iron, magnesium, copper and manganese, and their changes were discrepant in the period of harvest. The FP and SGP possessed the highest and lowest phenolic content, respectively. The change of SEP was significantly correlated to the SGP at different harvest times. The highest TPC was found for the root harvested at T3 and the most abundant phenolic acid was chlorogenic acid. The highest and lowest DPPH radical scavenging capacity was observed for the SGP and FP, respectively. The highest and lowest FRAP and TEAC were observed for the FP and SGP, respectively. The results of correlation analysis indicated that there was significant correlation between phenolic content and FRAP and TEAC, and different antioxidant assays. The microstructure of L. lucidus Turcz. root also varied greatly with the harvest times.

Stachyose-enriched α-galacto-oligosaccharides regulate gut microbiota and relieve constipation in mice

This study probed the effects of Deshipu stachyose granules (DSG), a novel oligosaccharide preparation (55.3% stachyose, 25.8% raffinose, and 9.7% verbascose), on gut microbiota and constipation in mice. Mice were administered intragastrically without or with DSG (0.42, 0.83, and 2.49 g/kg bw), and feces were collected after 14 days of treatment and subjected to classical microbiological assays. Selective index (SI) and prebiotic index (PI) were incorporated to evaluate the prebiotic effect. DSG at 0.83 g/kg bw scored the highest SI and PI scores, thus supporting a strong prebiotic role. In addition, the impact of DSG (0.42, 0.83, and 1.68 g/kg bw) on defecation function of constipated mice was determined. Ink propulsion rate in the small intestine was significantly improved by DSG treatment. DSG supplementation also distinctly increased the weight and number of black feces within 5 h and evidently shortened the defecating time of first black feces, as compared with the constipation control mice. All of these findings indicate that DSG may promote the growth of beneficial intestinal bacteria and inhibit pathogenic bacteria and also facilitate intestinal peristalsis and fecal excretion, thereby enhancing intestinal health and relieving constipation.

The aqueous extract of Lycopus lucidus Turcz ameliorates streptozotocin-induced diabetic renal damage via inhibiting TGF-β1 signaling pathway

PURPOSE

Renal fibrosis characterized by accumulation of extracellular matrix protein results in chronic renal diseases including diabetic nephropathy. Transforming growth factor β1 (TGF-β1) signaling pathway plays a key role in mediating renal fibrosis. Hence, agents that antagonize TGF-β signaling could be candidate for kidney disease therapy.

METHODS

We established renal fibrosis model both in vitro with fibroblast cells treated with rhTGF-β1 and streptozocin(STZ)-induced diabetic nephropathy rats model in vivo and evaluated the effect of the aqueous extract of Lycopus lucidus Turcz, the blood-circulation-promoting Chinese herb, on diabetic nephropathy and investigated the mechanism of action.

RESULTS

We found that Lycopus suppressed rhTGF-β1-induced Smad2 and ERK1/2 activation, down-regulated the expression of TGF-βRI, TGF-βRII, Smad4 and Smad7 in SV40 MES13 cells without inhibiting cell viability. In vivo, lycopus inhibited Smad2 phosphorylation, reduced mRNA level of TGF-β1, ameliorated expansion of the mesangial area in glomerular tissue and reduced the levels of Scr and BUN of serum and total-SOD (superoxide dismutase) activity in STZ-induced diabetic rats.

CONCLUSION

Lycopus is a novel inhibitor of renal fibrosis by blocking TGF-β signaling pathway and possess a protective effect on renal damage of STZ-induced diabetic nephropathy in rats.

Acaricidal activities of the active component of Lycopus lucidus oil and its derivatives against house dust and stored food mites (Arachnida: Acari)

BACKGROUND

Recent studies have focused on materials derived from plant extracts as mite control products against house dust and stored food mites because repeated use of synthetic acaricides had led to resistance and unwanted activities on non-target organisms. The aim of this study was to evaluate the acaricidal activity of materials derived from Lycopus lucidus against Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae.

RESULTS

The LD50 values of L. lucidus oil were 2.19, 2.25 and 8.45 µg cm(-2) against D. farinae, D. pteronyssinus and T. putrescentiae. The acaricidal constituent of L. lucidus was isolated by chromatographic techniques and identified as 1-octen-3-ol. In a fumigant method against D. farinae, the acaricidal activity of 1-octen-3-ol (0.25 µg cm(-2)) was more toxic than N,N-diethyl-m-toluamide (DEET) (36.84 µg cm(-2)), followed by 3,7-dimethyl-1-octen-3-ol (0.29 µg cm(-2)), 1-octen-3-yl butyrate (2.32 µg cm(-2)), 1-octen-3-yl acetate (2.42 µg cm(-2)), 3,7-dimethyl-1-octene (9.34 µg cm(-2)) and benzyl benzoate (10.02 µg cm(-2)). In a filter paper bioassay against D. farinae, 1-octen-3-ol (0.63 µg cm(-2)) was more effective than DEET (20.64 µg cm(-2)), followed by 3,7-dimethyl-1-octen-3-ol (1.09 µg cm(-2)).

CONCLUSION

1-Octen-3-ol and 3,7-dimethyl-1-octen-3-ol could be useful as natural agents for the management of three mite species.

Isolation, characterization, and immunological effects of alpha-galacto-oligosaccharides from a new source, the herb Lycopus lucidus Turcz

This study was designed to isolate and characterize a mixture of alpha-galacto-oligosaccharides (GOS) from a new source, the roots of Lycopus lucidus Turcz. (RL), a traditional dietary treatment. In this study, the chemical components and immunological function of RL-GOS were investigated. HPLC analysis showed that the purified RL-GOS was a typical raffinose family oligosaccharide (RFO) with a high stachyose content of 51.8% (w/w), followed by 26.5% raffinose and 10.1% verbascose. Further functional evaluation showed that RL-GOS could elicit a significant increase (p < 0.05 vs control) in humoral immunity, as measured by plaque-forming cell (PFC) generation and serum hemolysin level in response to sheep red blood cells (SRBC) at all three tested doses of RL-GOS (0.75, 1.5, and 3.0 g/kg of BW) in mice. In addition, the cellular immune activity of RL-GOS was also demonstrated by enhancing in vivo delayed-type hypersensitivity (DTH) reaction to SRBC and spleenocyte proliferation response to concanavalin A (p < 0.05, compared with control group). Nevertheless, there were no significant differences in weight gain, lymphoid organ indices, and phagocytosis capacity following RL-GOS treatment. This study provides evidence for the discovery of a new GOS source (20% w/w GOS in fresh roots of L. lucidus Turcz.) and its potential application as an immune stimulant in functional foods.

Composition and systemic immune activity of the polysaccharides from an herbal tea (Lycopus lucidus Turcz)

This study was undertaken to characterize the water-soluble polysaccharides isolated from an herbal tea, the leaves of L. lucidus Turcz. HPLC analysis showed that L. lucidus polysaccharides (LLPs) were mainly composed of galactose (50.1 mol %), followed by galacturonic acid (14.2 mol %), accounting for 64.3 mol % of all quantitative nine monosaccharides. Furthermore, we evaluated the systemic immunological efficacy of LLPs in mice. Mice were intragastrically administered once daily with low-dose (50 mg/kg), intermediate-dose (100 mg/kg), and high-dose (300 mg/kg) of LLPs, respectively, for 30 consecutive days. In comparison with vehicle, LLPs significantly enhanced the plaque-forming cells (PFCs), and serum hemolysin level, and delayed-type hypersensitivity (DTH) in response to sheep red blood cells (SRBC) in a dose-dependent manner (p < 0.01). In LLPs-treated mice, phagocytosis capacity and concanavalin A-induced spleenocyte proliferation were remarkably increased (p < 0.05). The intermediate- and high-dose of LLPs also caused a significant increase in the indices of thymus and spleen organs of mice (p < 0.05). This suggests that the polysaccharides derived from the tea leaves of L. lucidus improves the immune system and might be regarded as a biological response modifier.

[HPLC determination of caffeic acid in herba Lycopi]

OBJECTIVE

To provide experimental data for the quality control of processed Paeonia lactiflora, a Chinese herbal medicine.

METHOD

Traditional processing of P. lactiflora was simulated, content of paeoniflorin and water extracts among different preparations were assayed by HPLC; The quantitative correlations among different processing conditions were analyzed, the effects of processing parameters on the contents of paeoniflorin and water extracts were assayed and analysed.

RESULT AND CONCLUSION

The controlled processing parameters were correlated with covariables which showed that processing procedures was controllable, and the heating temperature was a factor impacting the content of paeoniflorin.

Extract of Lycopus europaeus L. reduces cardiac signs of hyperthyroidism in rats

Extracts from the plant Lycopus europaeus L. are traditionally used in mild forms of hyperthyroidism. High doses caused a reduction of TSH or thyroid hormone levels in animal experiments, whereas in hyperthyroid patients treated with low doses of Lycopus an improvement of cardiac symptoms was reported without major changes in TSH or thyroid hormone concentrations. Lycopus extract was tested in thyroxine treated hyperthyroid rats (0.7 mg/kg BW i.p.). Co-treatment with an hydroethanolic extract from L. europaeus L. started one week later than T4-application and lasted 5.5 weeks. As reference substance atenolol was used. The raised body temperature was reduced very effectively even by the low dose of the plant extract, whereas the reduced gain of body weight and the increased food intake remained unaffected by any treatment. No significant changes of thyroid hormone concentrations or TSH levels were observed. Lycopus extract and atenolol reduced the increased heart rate and blood pressure. The cardiac hypertrophy was alleviated significantly by both treatment regimes. beta-Adrenoceptor density in heart tissue was significantly reduced by the Lycopus extract or the beta-blocking agent showing an almost equal efficacy. Although the mode of action remains unclear, these organo-specific anti-T4-effects seem to be of practical interest, for example in patients with latent hyperthyroidism.

Human ACAT-1 and ACAT-2 inhibitory activities of pentacyclic triterpenes from the leaves of Lycopus lucidus TURCZ

Acyl-CoA: cholesterol acyltransferase (ACAT) catalyzes the acylation of cholesterol to cholesteryl ester with long chain fatty acids and ACAT inhibition is a useful strategy for treating hypercholesterolemia or atherosclerosis. Pentacyclic triterpenes, ursolic acid (1), oleanolic acid (2), and betulinic acid (3) were isolated from the methanol extracts of the leaves of Lycopus lucidus TURCZ. by bioassay-guided fractionation. The structures of compounds 1-3 were elucidated by their spectroscopic data analysis. Among them, betulinic acid (3) exhibited more potent human ACAT-1 and ACAT-2 inhibitory activities with IC(50) values of 16.2+/-0.6 and 28.8+/-1.3 microM, respectively.

Anti-allergic effects of Lycopus lucidus on mast cell-mediated allergy model

The current study characterizes the mechanism by which the aqueous extract of Lycopus lucidus Turcz. (Labiatae) (LAE) decreases mast cell-mediated immediate-type allergic reaction. The immediate-type allergic reaction is involved in many allergic diseases such as asthma and allergic rhinitis. LAE has been used as a traditional medicine in Korea and is known to have an anti-inflammatory effect. However, its specific mechanism of action is still unknown. LAE was anally administered to mice for high and fast absorption. LAE inhibited compound 48/80-induced systemic reactions in mice. LAE decreased the local allergic reaction, passive cutaneous anaphylaxis, activated by anti-dinitrophenyl (DNP) IgE antibody. LAE dose-dependently reduced histamine release from rat peritoneal mast cells activated by compound 48/80 or anti-DNP IgE. Furthermore, LAE decreased the secretion of TNF-alpha and IL-6 in phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-stimulated human mast cells. The inhibitory effect of LAE on the pro-inflammatory cytokine was p38 mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-kappaB) dependent. LAE attenuated PMA plus A23187-induced degradation of IkappaBalpha and nuclear translocation of NF-kappaB, and specifically blocked activation of p38 MAPK, but not that of c-jun N-terminal kinase and extracellular signal-regulated kinase. Our findings provide evidence that LAE inhibits mast cell-derived immediate-type allergic reactions and involvement of pro-inflammatory cytokines, p38 MAPK, and NF-kappaB in these effects.

Antioxidative constituents from Lycopus lucidus

Three phenolic compounds, rosmarinic acid (1), methyl rosmarinate (2), ethyl rosmarinate (3), and two flavonoids, luteolin (4), luteolin-7-O-beta-D-glucuronide methyl ester (5) were isolated from the aerial part of Lycopus lucidus (Labiatae). Their structures were determined by chemical and spectral analysis. Compounds 1-5 exhibited potent antioxidative activity on the NBT superoxide scavenging assay. The IC50 values for compounds 1-5 were 2.59, 1.42, 0.78, 2.83, and 3.05 microg/mL respectively. In addition, five compounds were isolated from this plant for the first time.

Bacterial resistance modifying agents from Lycopus europaeus

As part of an ongoing project to identify plant natural products which modulate bacterial multidrug resistance (MDR), bioassay-guided isolation of an extract of Lycopus europaeus yielded two new isopimarane diterpenes, namely methyl-1alpha-acetoxy-7alpha 14alpha-dihydroxy-8,15-isopimaradien-18-oate (1) and methyl-1alpha,14alpha-diacetoxy-7alpha-hydroxy-8,15-isopimaradien-18-oate (2). The structures were established by spectroscopic methods. These compounds and several known diterpenes were tested for in vitro antibacterial and resistance modifying activity against strains of Staphylococcus aureus possessing the Tet(K), Msr(A), and Nor(A) multidrug resistance efflux mechanisms. At 512 microg/ml none of the compounds displayed any antibacterial activity but individually in combination with tetracycline and erythromycin, a two-fold potentiation of the activities of these antibiotics was observed against two strains of S. aureus that were highly resistant to these agents due to the presence of the multidrug efflux mechanisms Tet(K) (tetracycline resistance) and Msr(A) (macrolide resistance).

[HPLC determination of oleanolic acid and llrolic acid in Chinese medicinal herbs]

OBJECTIVE

To develop a new method for simultaneous determination of oleanolic acid and llrolic acid in Chinese medicinal herbs at the same time.

METHOD

HPLC was carried out on a Shim-pack CLC-ODS column using MeOH-H2O-HOAc-TEA (83:17:0.04:0.02).

RESULT AND CONCLUSION

The average recovery of oleanolic acid and llrolic acid was 103.3 +/- 2.07% and 102.7% +/- 0.65% respectively.

[Effect of two extracted fraction from Lycopus lucidus on coagulation function]

OBJECTIVE

To find and define the effective fraction of Lycopus lucidus on coagulation.

METHODS

Method of comparing turbidity, method of cutting a part of the mice tail and method of breaking glass tube.

RESULTS

The two extracted fraction from lycopus lucidus F04-0A and F04-B could inhibit rats platlet aggregation in vitro and mice platelet aggregation in vivo. They could also prolong mice blood coagulation time. However, they had no effect on bleeding time.

CONCLUSION

Both F04-A and F04-B had effects on inhibiting platelet aggregation and blood coagulation. Moreover, the activity of F04-A was probably stronger than that of F04-B. F04-A may be the effective fraction from Lycopus lucidus on promoting blood circulation and removing blood stasis.