Study of the Structure and Bioactivity of Polysaccharides from Different Parts of Stemona tuberosa Lour.

The polysaccharides from Stemona tuberosa Lour, a kind of plant used in Chinese herbal medicine, have various pharmacological activities, such as anti-inflammatory and antioxidant properties. However, the effects of the extraction methods and the activity of polysaccharides from different parts are still unknown. Therefore, this study aimed to evaluate the effects of different extraction methods on the yields, chemical compositions, and bioactivity of polysaccharides extracted from different parts of Stemona tuberosa Lour. Six polysaccharides were extracted from the leaves, roots, and stems of Stemona tuberosa Lour through the use of hot water (i.e., SPS-L1, SPS-R1, and SPS-S1) and an ultrasound-assisted method (i.e., SPS-L2, SPS-R2, and SPS-S2). The results showed that the physicochemical properties, structural properties, and biological activity of the polysaccharides varied with the extraction methods and parts. SPS-R1 and SPS-R2 had higher extraction yields and total sugar contents than those of the other SPSs (SPS-L1, SPS-L2, SPS-S1, and SPS-S2). SPS-L1 had favorable antioxidant activity and the ability to downregulate MUC5AC expression. An investigation of the anti-inflammatory properties showed that SPS-R1 and SPS-R2 had greater anti-inflammatory activities, while SPS-R2 demonstrated the strongest anti-inflammatory potential. The results of this study indicated that SPS-L1 and SPS-L2, which were extracted from non-medicinal parts, may serve as potent natural antioxidants, but further study is necessary to explore their potential applications in the treatment of diseases. The positive anti-inflammatory effects of SPS-R1 and SPS-R2 in the roots may be further exploited in drugs for the treatment of inflammation.

Identification of sedative-hypnotic compounds shared by five medicinal Polyporales mushrooms using UPLC-Q-TOF-MS/MS-based untargeted metabolomics.

BACKGROUND: Five Polyporales mushrooms, namely Amauroderma rugosum, Ganoderma lucidum, G. resinaceum, G. sinense and Trametes versicolor, are commonly used in China for managing insomnia. However, their active components for this application are not fully understood, restricting their universal recognition. PURPOSE: In this study, we aimed to identify sedative-hypnotic compounds shared by these five Polyporales mushrooms. STUDY DESIGN AND METHODS: A UPLC-Q-TOF-MS/MS-based untargeted metabolomics, including OPLS-DA (orthogonal projection of potential structure discriminant analysis) and OPLS (orthogonal projections to latent structures) analysis together with mouse assays, were used to identify the main sedative-hypnotic compounds shared by the five Polyporales mushrooms. A pentobarbital sodium-induced sleeping model was used to investigate the sedative-hypnotic effects of the five mushrooms and their sedative-hypnotic compounds. RESULTS: Ninety-two shared compounds in the five mushrooms were identified. Mouse assays showed that these mushrooms exerted sedative-hypnotic effects, with different potencies. Six triterpenes [four ganoderic acids (B, C1, F and H) and two ganoderenic acids (A and D)] were found to be the main sedative-hypnotic compounds shared by the five mushrooms. CONCLUSION: We for the first time found that these six triterpenes contribute to the sedative-hypnotic ability of the five mushrooms. Our novel findings provide pharmacological and chemical justifications for the use of the five medicinal mushrooms in managing insomnia.

Epigallocatechin gallate circumvents drug-induced resistance in non-small-cell lung cancer by modulating glucose metabolism and AMPK/AKT/MAPK axis.

Upon prolonged use of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in non-small-cell lung cancer (NSCLC), acquired drug resistance inevitably occurs. This study investigates the combined use of EGFR-TKIs (gefitinib or osimertinib) with epigallocatechin gallate (EGCG) to overcome acquired drug resistance in NSCLC models. The in vitro antiproliferative effects of EGFR-TKIs and EGCG combination in EGFR-mutant parental and resistant cell lines were evaluated. The in vivo efficacy of the combination was assessed in xenograft mouse models derived from EGFR-TKI-resistant NSCLC cells. We found that the combined use of EGFR-TKIs and EGCG significantly reversed the Warburg effect by suppressing glycolysis while boosting mitochondrial respiration, which was accompanied by increased cellular ROS and decreased lactate secretion. The combination effectively activated the AMPK pathway while inhibited both ERK/MAPK and AKT/mTOR pathways, leading to cell cycle arrest and apoptosis, particularly in drug-resistant NSCLC cells. The in vivo results obtained from mouse tumor xenograft model confirmed that EGCG effectively overcame osimertinib resistance. This study revealed that EGCG suppressed cancer bypass survival signaling and altered cancer metabolic profiles, which is a promising anticancer adjuvant of EGFR-TKIs to overcome acquired drug resistance in NSCLC.

A tri-herb formulation protects against ethanol-induced mouse liver injury and downregulates mitogen-activated protein kinase phosphatase 1.

BACKGROUND: A tri-herb formulation comprising Ganoderma (the dried fruiting body of Ganoderma lucidum), Puerariae Thomsonii Radix (the dried root of Pueraria thomsonii) and Hoveniae Semen (the dried mature seed of Hovenia acerba) -GPH for short- has been using for treating liver injury; however, the pharmacological basis of this application of GPH is unknown. This study aimed to investigate the liver protective effects and mechanisms of action of an ethanolic extract of GPH (GPHE) in mice. METHODS: To control the quality of GPHE, the contents of ganodermanontriol, puerarin and kaempferol in the extract were quantified by ultra-performance liquid chromatography. An ethanol (6 ml/kg, i.g.)-induced liver injury ICR mouse model was employed to investigate the hepatoprotective effects of GPHE. RNA-sequencing analysis and bioassays were performed to reveal the mechanisms of action of GPHE. RESULTS: The contents of ganodermanontriol, puerarin and kaempferol in GPHE were 0.0632%, 3.627% and 0.0149%, respectively. Daily i.g. administration of 0.25, 0.5 or 1 g/kg of GPHE for 15 consecutive days suppressed ethanol (6 ml/kg, i.g., at day 15)-induced upregulation of serum AST and ALT levels and improved histological conditions in mouse livers, indicating that GPHE protects mice from ethanol-induced liver injury. Mechanistically, GPHE downregulated the mRNA level of Dusp1 (encoding MKP1 protein, an inhibitor of the mitogen-activated protein kinases JNK, p38 and ERK), and upregulated expression and phosphorylation of JNK, p38 and ERK, which are involved in cell survival in mouse liver tissues. Also, GPHE increased PCNA (a cell proliferation marker) expression and reduced TUNEL-positive (apoptotic) cells in mouse livers. CONCLUSION: GPHE protects against ethanol-induced liver injury, and this effect of GPHE is associated with regulation of the MKP1/MAPK pathway. This study provides pharmacological justifications for the use of GPH in treating liver injury, and suggests that GPHE has potential to be developed into a modern medication for managing liver injury.

Ultrasonic assisted extraction, characterization and gut microbiota-dependent anti-obesity effect of polysaccharide from Pericarpium Citri Reticulatae 'Chachiensis'.

Pericarpium Citri Reticulatae 'Chachiensis' (PCRC), the premium aged pericarps of Pericarpium Citri Reticulatae, is widely used in traditional Chinese medicines with a diversity of promising bioactivity. Herein we report the extraction, characterization and underlying mechanism of anti-metabolic syndrome of an arabinan-rich polysaccharide from PCRC (PCRCP). This polysaccharide was obtained in a 7.0% yield by using ultrasound-assisted extraction under the optimized conditions of 30 mL/g liquid-to-solid ratio, 250 W ultrasound power for 20 min at 90 °C with pH 4.5. The PCRCP with an average molecular weight of 122.0 kDa, is mainly composed of D-galacturonic acid, arabinose and galactose, which may link via 1,4-linked Gal(p)-UA, 1,4-linked Ara(f) and 1,4-linked Gal(p). Supplementation with PCRCP not only effectively alleviated the weight gain, adiposity and hyperglycemia, but also regulated the key metabolic pathways involved in the de novo synthesis and ß-oxidation of fatty acid in high-fat diet (HFD)-fed mice. Furthermore, PCRCP treatment caused a significant normalization in the intestinal barrier and composition of gut microbiota in mice fed by HFD. Notably, PCRCP selectively enriched Lactobacillus johnsonii at the family-genus-species levels, a known commensal bacterium, the level of which was decreased in mice fed by HFD. The depletion of microbiome induced by antibiotics, significantly compromised the effects of anti-metabolic syndrome of PCRCP in mice fed by HFD, demonstrating that the protective phenotype of PCRCP against anti-obesity is dependent on gut microbiota. PCRCP is exploitable as a potential prebiotic for the intervention of obesity and its complications.

Design, Synthesis and Antitumor Activity of Novel Selenium-Containing Tepotinib Derivatives as Dual Inhibitors of c-Met and TrxR.

Cellular mesenchymal-epithelial transition factor (c-Met), an oncogenic transmembrane receptor tyrosine kinase (RTK), plays an essential role in cell proliferation during embryo development and liver regeneration. Thioredoxin reductase (TrxR) is overexpressed and constitutively active in most tumors closely related to cancer recurrence. Multi-target-directed ligands (MTDLs) strategy provides a logical approach to drug combinations and would adequately address the pathological complexity of cancer. In this work, we designed and synthesized a series of selenium-containing tepotinib derivatives by means of selenium-based bioisosteric modifications and evaluated their antiproliferative activity. Most of these selenium-containing hybrids exhibited potent dual inhibitory activity toward c-Met and TrxR. Among them, compound 8b was the most active, with an IC50 value of 10 nM against MHCC97H cells. Studies on the mechanism of action revealed that compound 8b triggered cell cycle arrest at the G1 phase and caused ROS accumulations by targeting TrxR, and these effects eventually led to cell apoptosis. These findings strongly suggest that compound 8b serves as a dual inhibitor of c-Met and TrxR, warranting further exploitation for cancer therapy.

AIE-based gold nanostar-berberine dimer nanocomposites for PDT and PTT combination therapy toward breast cancer.

We designed and synthesized three new berberine-based compounds, namely, pyridine-2,6-dimethyl-/2,2'-bipyridine-3,3'-dimethyl-tethered berberine dimers BD1 and BD2, and a tetrakis(4-benzyl)ethylene linked berberine tetramer BD4. We identified that the dimer BD2 and tetramer BD4, as well as 1,10-phenanthroline-2,9-dimethyl-linked berberine dimer BD3 previously reported by us, showed remarkable aggregation-induced emission (AIE) properties which endowed them with higher singlet oxygen (1O2) production ability than berberine. Of the four compounds, BD3 exhibits the lowest ΔEST energy with the highest 1O2 generation ability and thus was selected for further construction of AuNSs-BD3@HA (denoted as ABH, AuNSs = gold nanostars; HA = hyaluronic acid). The nanosystem of ABH shows a remarkable therapeutic effect toward breast cancer by combining photodynamic therapy (PDT) from BD3, photothermal therapy (PTT) from AuNSs, and the CD44-targeting capability of HA. The synergistically enhanced PDT and PTT induce superior cancer cell apoptosis/necrosis in vitro and anti-breast cancer activity in vivo. This study provides a new concept for PDT using natural product derivatives and their combination with PTT for efficient treatment of tumors.

Isolation, structural properties, bioactivities of polysaccharides from Dendrobium officinale Kimura et. Migo: A review.

Dendrobium officinale Kimura et Migo (D. officinale) is used as herbal medicine and new food resource in China, which is nontoxic and harmless, and can be used as common food. Polysaccharide as one of the main bioactive components in D. officinale, mainly composed of glucose and mannose (Manp: Glcp = 2.01:1.00-8.82:1.00), along with galactose, xylose, arabinose, and rhamnose in different molar ratios and types of glycosidic bonds. Polysaccharides of D. officinale exhibit a variety of biological effects, including immunomodulatory, anti-tumor, gastro-protective, hypoglycemic, anti-inflammatory, hepatoprotective, and vasodilating effects. This paper presents the extraction, purification, structural characteristics, bioactivities, structure-activity relationships and analyzes gaps in the current research on D. officinale polysaccharides. In addition, based on in vitro and in vivo experiments, the possible mechanisms of bioactivities of D. officinale polysaccharides were summarized. We hope that this work may provide helpful references and promising directions for further study and development of D. officinale polysaccharides.

Cynanchum bungei Decne and its two related species for "Baishouwu": A review on traditional uses, phytochemistry, and pharmacological activities.

ETHNOPHARMACOLOGICAL RELEVANCE: Cynanchum bungei Decne. (CB) (Asclepiadaceae) and its two related species Cynanchum auriculatum Royle ex Wight. (CA) and Cynanchum wilfordii (Maxim.) Hemsl. (CW) are well known Chinese herbal medicines known by the name Baishouwu. Among them, CB has long been used for nourishing the kidney and liver, strengthening the bones and muscles, and regulating stomachache. However, to date, no comprehensive review on Baishouwu has been published. AIM OF THE REVIEW: This review aims to provide a comprehensive summary on traditional uses, phytochemistry, pharmacology, and toxicology of the three herbal components of Baishouwu with the ultimate objective of providing a guide for future scientific and therapeutic potential use of Baishouwu. MATERIAL AND METHODS: A literature search was undertaken on CB, CA and CW by analyzing the information from scientific databases (SciFinder, Pubmed, Elsevier, Google Scholar, Web of Science, and Baidu Scholar). Information was also gathered from local classic herbal literatures and conference papers on ethnopharmacology and the information provided in this review has been obtained from peer-reviewed papers. RESULTS: Comparative analysis of literature search indicate that ethnopharmacological use of CB was recorded in China, however, CA and CW have been used in China, Korea and Japan. To date, 151 chemical compounds have been isolated from these species, and the major chemical constituents have been revealed to be acetophenones, C21-steroids, terpenoids, and alkaloids. These compounds and extracts have been proven to exhibit significant pharmacological activities, including anti-tumor, anti-inflammatory, immunomodulatory, hypolipidemic, anti-obesity, hepatoprotective, antifungal, antiviral, anti-depressant, vasodilating and estrogenic activities. CONCLUSIONS: CB, CA and CW collectively known as Baishouwu are valuable medicinal herbs with multiple pharmacological activities. The traditional use for nourishing liver is closely associated with the hepatoprotective activity. The available literature performs that various of the activity of Baishouwu can be attributed to acetophenones and C21-steroids. It is high time that more efforts should be focused on the underlying mechanisms of their beneficial bioactivities and the structure activity relationship of the constituents, as well as their potential synergistic and antagonistic effects. The proper toxicology evaluation is crucial to guarantee the safety, efficacy, and eligibility for medical use. Further research on the comprehensive evaluation of medicinal quality and the understanding of multi-target network pharmacology of Baishouwu is in great request.

A zinc(II)-based two-dimensional MOF for sensitive and selective sensing of HIV-1 ds-DNA sequences.

Coordination reaction of a known three-dimensional (3D) polymer precursor {Na3[Na9(Cbdcp)6(H2O)18]}n (A, Cbdcp = N-(4-carboxybenzyl)-(3,5-dicarboxyl)pyridinium) with Zn(NO3)2·6H2O in H2O or H2O/DMF at 100 °C and in the presence of aspirin, 5-fluorouracil (5-FU) as modulators, trans-1,2-bis(4-pyridyl)ethylene (bpe) or 1,2-bis(4-pyridyl)ethane (bpea) as ancillary ligands afforded six novel Zn(II)-based metal-organic frameworks (MOFs), that is, {[Zn(Cbdcp)(H2O)3]·H2O}n (1, 1D zigzag chain), {[Zn(HCbdcp)2]·H2O}n (2, 2D sheet), {[Zn(Cbdcp)(bpe)1/2]·2H2O}n (3, 3D polymer), {[Zn(Cbdcp)(bpe)1/2]·2H2O}n (4, 2D network), {[Zn(Cbdcp)(bpea)1/2]·2H2O}n (5, 3D polymer) and {[Zn(Cbdcp)(bpea)1/2]·2H2O}n (6, 2D network). Among them, compound 2 contains aromatic rings, positively charged pyridinium, Zn(2+) cation centers and carboxylic acid groups lined up on the 2D sheet structure with a certain extended surface exposure. The unique structure of 2 facilitates effective association with carboxyfluorescein (FAM) labeled probe single stranded DNA (probe ss-DNA, delineates as P-DNA) to yield a P-DNA@2 system, and leads to fluorescence quenching of FAM via a photoinduced electron transfer process. The P-DNA@2 system is effective and reliable for the detection of human immunodeficiency virus 1 ds-DNA (HIV ds-DNA) sequences and capable of distinguishing complementary HIV ds-DNA from mismatched target sequences with the detection limit as low as 10 pM (S/N = 3).

A zwitterionic 1D/2D polymer co-crystal and its polymorphic sub-components: a highly selective sensing platform for HIV ds-DNA sequences.

Polymorphic compounds {[Cu(dcbb)2(H2O)2]·10H2O}n (2, 1D chain), [Cu(dcbb)2]n (3, 2D layer) and their co-crystal {[Cu(dcbb)2(H2O)][Cu(dcbb)2]2}n (4) have been prepared from the coordination reaction of a 2D polymer [Na(dcbb)(H2O)]n (1, H2dcbbBr = 1-(3,5-dicarboxybenzyl)-4,4'-bipyridinium bromide) with Cu(NO3)2·3H2O at different temperatures in water. Compounds 2-4 have an identical metal-to-ligand stoichiometric ratio of 1 : 2, but absolutely differ in structure. Compound 3 features a 2D layer structure with aromatic rings, positively charged pyridinium and free carboxylates on its surface, promoting electrostatic, π-stacking and/or hydrogen-bonding interactions with the carboxyfluorescein (FAM) labeled probe single-stranded DNA (probe ss-DNA, delineates as P-DNA). The resultant P-DNA@3 system facilitated fluorescence quenching of FAM via a photoinduced electron transfer process. The P-DNA@3 system functions as an efficient fluorescent sensor selective for HIV double-stranded DNA (HIV ds-DNA) due to the formation of a rigid triplex structure with the recovery of FAM fluorescence. The system reported herein also distinguishes complementary HIV ds-DNA from mismatched target DNA sequences with the detection limit of 1.42 nM.

Soy isoflavone supplementation could reduce body weight and improve glucose metabolism in non-Asian postmenopausal women--a meta-analysis.

OBJECTIVE: The objective of this study was to conduct a systematic review and a meta-analysis to confirm the effects of soy isoflavone supplementation on body weight, fasting glucose, and insulin level in non-Asian postmenopausal women. METHODS: We searched the PubMed, EMBASE, and Cochrane databases up to October 2010 for randomized controlled trials regarding the effects of isoflavone supplementation on body weight, fasting glucose, and insulin level. Pooled estimates and 95% confidence intervals (CIs) were calculated by the fixed-and-random-effects model. RESULTS: Nine studies with 528 participants for body weight, 11 studies with 1182 participants for fasting glucose, and 11 studies with 1142 participants for fasting insulin were included, respectively. Significant reductions were found in body weight [weighted mean difference (WMD), -0.515; 95%CI: -0.895 to -0.134; P = 0.008), glucose level (WMD, -0.189; 95%CI: -0.344 to -0.033), and fasting insulin level (WMD, -0.940; 95%CI: -1.721 to -0.159) with soy isoflavone supplementation compared with placebo control group in non-Asian postmenopausal women after adjusted by unpublished studies. Furthermore, isoflavone supplementation in shorter duration (<6 mo) could significantly reduce body weight (WMD, -0.506; 95%CI: -0.888 to -0.124; P = 0.009) and longer duration (≥ 6 mo) could significantly reduce blood glucose in postmenopausal women (WMD, -0.270; 95%CI: -0.430 to -0.110; P = 0.001). Meanwhile, more reduction in body weight was observed in the lower dose subgroup (dose < 100 mg). Moreover, it is more effective to reduce body weight and fasting insulin level with soy isoflavone supplementation in normal weight (body mass index < 30) than obese (body mass index ≥ 30) women. CONCLUSIONS: This meta-analysis showed soy isoflavone supplementation could be beneficial for body weight reduction, glucose, and insulin control in plasma. Large and well-designed studies are recommended to confirm this conclusion.

Effects of phytoestrogen on mitochondrial structure and function of hippocampal CA1 region of ovariectomized rats.

The present study was undertaken to evaluate whether estrogen deprivation might lead to mitochondrial alteration of hippocampal neurons of ovariectomized (OVX) rats, and to evaluate the protective effect of estrogen and phytoestrogen on the mitochondrial alteration. First, OVX rats were used to mimic the pathologic changes of neurodegeneration of postmenopausal female, and we looked into the alteration of the mitochondrial ultrastructure and ATP content of hippocampal CA1 region after ovariectomy on different phase by transmission electron microscope (TEM) and reversed-phase high-performance liquid chromatography (HPLC), and found the best phase points of the alteration of the mitochondrial ultrastructure and ATP content. Next, estrogen and phytoestrogen were administered to the OVX rats for the protective effects on the mitochondrial ultrastructure and ATP content. Meanwhile, the density, size, shape, and distribution parameters of mitochondrial ultrastructure were analyzed according to the morphometry principle. The experimental results presented that (1) The alteration of mitochondrial ultrastructure elicited by ovariectomy worsened with the days going on, and the changes were the most noteworthy in volume density (Vv), average surface area (S), specific surface area (delta), and particle dispersity (Clambdaz) on 12th day (P < 0.05 or P < 0.01). Moreover, there was no statistical significance of the numerical density (Nv) among the five groups in the first step experiment. (2) The treatment with estrogen, genistein (Gs), and ipriflavone (Ip) significantly reversed the effect elicited by ovariectomy on Vv, S, delta, Clambdaz, Nv, and particle average diameter (D) of mitochondria of hippocampal CA1 region (P < 0.05). (3) Furthermore, ATP content of hippocampal CA1 region after ovariectomy declined significantly on 7th day (P < 0.05), and estrogen and phytoestrogen could reverse the alteration (P < 0.05). Taken together, these results revealed that phytoestrogen may have a protective role against the neurodegeneration after menopause via protecting mitochondrial structure and functions. Phytoestrogen may be a good alternative as a novel therapeutic strategy for menopausal syndrome.

DNA-binding affinities and sequence specificities of protoberberine alkaloids and their demethylated derivatives: a comparative study.

Berberrubine (1a), jatrorubine (2a), and palmatrubine (3a) have been chemically prepared by partial demethylation of berberine (1), jatrorrhizine (2), and palmatine (3), respectively. Their interactions with calf thymus (CT) DNA, poly(dA-dT)poly(dA-dT), poly(dG-dC)poly(dG-dC), and eight AT-rich 12-mer double-stranded DNAs have been investigated by means of competitive ethidium bromide (EB) displacement experiments. The results showed that DNA-binding affinities of these protoberberine alkaloids have been significantly improved by partial demethylation, and that all of these alkaloids have the preferable binding affinities with AT-rich DNA. Especially, the sequence specificities of DNA-binding of demethylated derivatives 1a, 2a, and 3a had changed to a certain extent when compared with the parent alkaloids 1, 2, and 3, respectively. The binding mode of these alkaloids was further confirmed by UV spectroscopic titration experiments. All the compounds bind to double-stranded DNA most probably via an intercalating mode.

[Effects of soybean isoflavone on body weight and food utilization rate in ovariectomized rats].

OBJECTIVE: To investigate the inhibitory action of phytoestrogen soybean isoflavone on body weight increasing in ovariectomized rats that imitated postmenopausal women and the effect of decreasing food availability. METHODS: Four-month-old Wistar rats were sham-operated or ovariectomized by abdominal cavity operation and divided into Sham, Ovx, estrogen group(EC) and three isoflavone group and feed 16 weeks. The diet was prepared by ourselves and some contained diethylstilbestrol or different concentration of isoflavone. During the experiment, the rats weight and food intake were recorded. The food utilization rates of each group were calculated. RESULTS: The result showed that high dosage of soybean isoflavone (187.4 mg/kg bw x d) can significantly inhibited OVX induced weight gain and inhibitory action decreased with the dose reduce. Compared with Sham and Ovx group, the food intake of isoflavone group decreased significantly but no different in 3 dosage group and higher than EC group. Compared with Ovx group, the food utilization rates of high isoflavone group decreased significantly but higher than EC group. Isoflavone not influenced the growth and organ/body rates of rats. CONCLUSION: High dosage of isoflavone (187.4mg/kg bw x d) decreased OVX rat's weight gain significantly through reducing food utilization rate.

Study on noncovalent complexes of cytotoxic protoberberine alkaloids with double-stranded DNA by using electrospray ionization mass spectrometry.

The noncovalent complexes of four cytotoxic protoberberine alkaloids that is, berberine, palmatine, jatrorrhizine, and coptisine with double-stranded oligodeoxynucleotides d(AAGAATTCTT)(2) were investigated by electrospray ionization mass spectrometry. These four active components from Chinese herbal medicines showed both 1:1 and 1:2 binding stoichiometries, independent on the alkaloid-to-DNA ratios. Binding affinities in the order of palmatine> or =jatrorrhizine>coptisine>berberine with d(AAGAATTCTT)(2) were obtained. Additionally, the preliminary results indicated that berberine had some sequence selectivities.