Sangeeta R. Mehendale

Commonly Used Antioxidant Botanicals: Active Constituents and their Potential Role in Cardiovascular Illness

Cardiovascular disease continues to be the leading cause of death in the US. Recent studies found that reactive oxygen species (ROS) have been incriminated in the pathogenesis of both acute and chronic heart disease. Many botanicals possess antioxidant properties, and these herbal antioxidants may protect against cardiovascular diseases by contributing to the total antioxidant defense system of the human body. In this article, we reviewed the antioxidant components and properties of four putative antioxidant botanicals (i.e., grape seeds, green tea, Scutellaria baicalensis, and American ginseng), and their potential role in treating cardiovascular illness. The antioxidant activities of the herbal active constituents, and the relationship between their chemical structures and biological functions were also discussed. Further investigations are needed on the mechanisms of action of these botanicals as they affect salient cellular and molecular pathways involved in major diseases. Data obtained from future studies will have the potential for translation into practical benefits for human health.

Anti-diabetic effects of Gymnema yunnanense extract

In this study, we evaluated anti-hyperglycemic effect and body weight reduction activity of Gymnema yunnanense extract in obese ob/ob and diabetic db/db mice. Animals received daily intraperitoneal injections of the extract 100 mg/kg for 12 days. On Day 5, the extract-treated ob/ob mice had significantly lower fasting blood glucose levels compared to vehicle-treated mice (161+/-14.5mg/dl versus 238+/-21.5mg/dl, P<0.01). On Day 12, the extract-treated ob/ob mice had normal fasting blood glucose levels, compared with vehicle-treated mice (119+/-3.3mg/dl versus 240+/-12.9 mg/dl, P<0.01). Glucose tolerance improved significantly. This was demonstrated by overall glucose excursion calculated as area under the curve (AUC) during the 2h intraperitoneal glucose tolerance test (IPGTT), which decreased by approximately 22% (P<0.01) compared to vehicle-treated ob/ob mice. In addition, extract-treated ob/ob mice lost weight significantly from 51.7+/-1.9 g on Day 0 to 45.7+/-1.2g on Day 12 (P<0.05 compared to vehicle-treated mice). In db/db mice, after treatment with same dose of the extract, fasting blood glucose levels also decreased significantly from Day 0 of 247+/-13.9 mg/dl to Day 5 of 172+/-7.5mg/dl and to Day 12 of 190+/-2.7 mg/dl (both P<0.01 compared to vehicle-treated group from Day 0 of 239+/-12.1mg/dl to Day 5 of 230+/-8.5mg/dl and Day 12 of 247+/-18.9 mg/dl, respectively). After 12 days of extract treatment, body weight in db/db mice reduced from 61.8+/-1.4 g on Day 0 to 59.8+/-1.1g on Day 12 (P<0.05). Our results support an in vivo anti-hyperglycemic and body weight reduction activity of G. yunnanense extract that may prove to be of clinical importance in improving the management of type 2 diabetes.

Anti-hyperglycemic effect of the polysaccharides fraction from American ginseng berry extract in ob/ob mice

In this study, we evaluated the anti-hyperglycemic effect of a polysaccharides fraction from American ginseng berry extract in diabetic ob/ob mice. All animals received daily intraperitoneal injections of polysaccharides at 150 mg/kg body wt. (n = 5), polysaccharides at 50 mg/kg body wt. (n = 5), or vehicle (n = 5) for 10 consecutive days. On Day 5, as compared to the vehicle-treated mice (230.5 +/- 13.5 mg/dl, mean +/- S.E), mice from both treated groups showed significantly lower fasting blood glucose levels (187.4 +/- 20.5 mg/dl and 187.4 +/- 17.1 mg/dl), respectively (both P < 0.05). On Day 10, compared to the vehicle group (240.1 +/- 12.3 mg/dl), the 50 mg/kg dose group were at 188.4 +/- 12.6 mg/dl (P < 0.05), and the 150 mg/kg dose group were normoglycemic (148.8 +/- 17.6 mg/dl, P < 0.01). Those ob/ob mice treated with vehicle did not, however, show significant changes in fasting blood glucose levels. Data from the intraperitoneal glucose tolerance test (IPGTT) showed that, compared to Day 0, there was a significant improvement in glucose tolerance in animals who received the 50 and 150 mg/kg polysaccharide doses, and the area under the curve (AUC) decreased 15.5% (P < 0.05) and 28.2% (P < 0.01), respectively. Interestingly, after cessation of polysaccharide treatment, the fasting blood glucose levels stayed lower, and returned to control concentration on Day 30. We also observed that the polysaccharides fraction did not affect body weight changes in ob/ob mice. Our data suggest that the polysaccharides fraction from American ginseng berry extract has a potential clinical utility in treating diabetic patients.

Asian ginseng enhances the anti-proliferative effect of 5-fluorouracil on human colorectal cancer: Comparison between white and red ginseng

Previous studies showed that Asian ginseng, Panax ginseng C.A. Meyer, may have anti-cancer properties. However, there is limited data exploring the use of Asian ginseng as an adjuvant to chemotherapy, and minimal mechanistic studies related to their possible synergistic activities. In this study, the content of 8 ginsenosides, Rb1, Rb2, Rb3, Rc, Rd, Re, Rg1 and Rg3, in the extracts of white ginseng (WG) and red ginseng (RG) were determined by HPLC. Using HCT-116 human colorectal cancer cells, we compared the efficacy of WG and RG. We evaluated the synergy between ginseng and 5-fluorouracil (5-FU), and explored the mechanism of their anti-proliferative effects. As single extract, WG or RG used at concentrations of 0.1, 0.2 and 0.3 mg/mL, inhibited HCT-116 cell proliferation in a concentration-related manner. WG at 0.2 mg/mL did not show obvious synergy with 5-FU co-treatment, while RG at 0.2 and 0.3 mg/mL significantly enhanced the anti-proliferative effects of 5-FU at concentrations of 10, 50 and 100 μM (P < 0.05). Using flow cytometric assay, RG 0.3 mg/mL did not affect cancer cell apoptotic induction activity. However, the RG induced cell cycle arrest in the G1 phase, while 5-FU arrested the cell in the S phase. Different ginsenoside profiles are responsible for the observed differences in pharmacological effects. The effects of 8 ginsenosides on HCT-116 cells were assayed. Rd and Rg3 showed positive anti-proliferative effect. Our data suggested a potential for RG as an adjuvant therapy in the treatment of colorectal cancer, via a synergistic action.

Detection of Adulteration of Notoginseng Root Extract with Other Panax Species by Quantitative HPLC Coupled with PCA

Reverse phase high-performance liquid chromatography (HPLC) coupled with a principal component analysis (PCA) method was used to distinguish the extract of notoginseng root from that of other species in the genus Panax . The content of 12 saponins in notoginseng root extracts from different sources was evaluated. Herbal extracts from different plant parts of notoginseng, Asian ginseng, and American ginseng were also evaluated. With an HPLC assay, however, it is difficult to determine whether notoginseng root extract has been adulterated with other plant parts or other Panax species before extraction. Therefore, PCA was introduced to identify adulteration in notoginseng root extract. PCA was performed on the data set obtained from the HPLC chromatogram. The HPLC-PCA assay distinguished notoginseng root extract not only from the extract of other plant parts of notoginseng but also from the extract of Asian or American ginseng plant parts.

Selective fraction of Scutellaria baicalensis and its chemopreventive effects on MCF-7 human breast cancer cells

Based on our previous observation, the whole Scutellaria baicalensis extract (SbE) did not show significant breast cancer cell inhibitory effect. In this study, we isolated a baicalin-deprived-fraction (SbF1) of Scutellaria baicalensis, and baicalin-fraction (SbF3), and evaluated their anti-breast cancer properties using MCF-7 cells. The content of four flavonoids in extract/fractions were determined using high performance liquid chromatography. Analytical data showed that in SbF1, the major constituents are baicalein and wogonin, while SbF3 only contains baicalin. The antiproliferative effects of fractions and SbE were assayed using modified trichrome stain method. SbF1 showed significant antiproliferative effect. Treated with 100mug/ml of SbF1 for 72h inhibited MCF-7 cell growth by 81.6%, while in the same treatment concentration, SbF3 increased cell growth by 22.6%. SbF1 was recognized as an active fraction of SbE. The effects of four flavonoids in SbE, scutellarin, baicalin, baicalein and wogonin, were determined, and data showed that baicalein and wogonin significantly inhibited MCF-7 cell growth. In contrast, in certain concentrations, scutellarin and baicalin increased cancer cell growth. The effects of SbF1 on cell cycle and apoptosis were assayed using flow cytometry. SbF1 arrested MCF-7 cells in S- and G2/M-phases, and significantly increased induction of cell apoptosis. These combined phytochemical and biological data provide evidence for further chemopreventive studies of the baicalin-deprived SbE on breast cancer.

Grape seed proanthocyanidins protect cardiomyocytes from ischemia and reperfusion injury via Akt‐NOS signaling

Ischemia/reperfusion (I/R) injury in cardiomyocytes is related to excess reactive oxygen species (ROS) generation and can be modulated by nitric oxide (NO). We have previously shown that grape seed proanthocyanidin extract (GSPE), a naturally occurring antioxidant, decreased ROS and may potentially stimulate NO production. In this study, we investigated whether GSPE administration at reperfusion was associated with cardioprotection and enhanced NO production in a cardiomyocyte I/R model. GSPE attenuated I/R‐induced cell death [18.0 ± 1.8% (GSPE, 50 µg/ml) vs. 42.3 ± 3.0% (I/R control), P < 0.001], restored contractility (6/6 vs. 0/6, respectively), and increased NO release. The NO synthase (NOS) inhibitor Nω‐nitro‐L‐arginine methyl ester (L‐NAME, 200 µM) significantly reduced GSPE‐induced NO release and its associated cardioprotection [32.7 ± 2.7% (GSPE + L‐NAME) vs. 18.0 ± 1.8% (GSPE alone), P < 0.01]. To determine whether GSPE induced NO production was mediated by the Akt‐eNOS pathway, we utilized the Akt inhibitor API‐2. API‐2 (10 µM) abrogated GSPE‐induced protection [44.3% ± 2.2% (GSPE + API‐2) vs. 27.0% ± 4.3% (GSPE alone), P < 0.01], attenuated the enhanced phosphorylation of Akt at Ser473 in GSPE‐treated cells and attenuated GSPE‐induced NO increases. Simultaneously blocking NOS activation (L‐NAME) and Akt (API‐2) resulted in decreased NO levels similar to using each inhibitor independently. These data suggest that in the context of GSPE stimulation, Akt may help activate eNOS, leading to protective levels of NO. GSPE offers an alternative approach to therapeutic cardioprotection against I/R injury and may offer unique opportunities to improve cardiovascular health by enhancing NO production and increasing Akt‐eNOS signaling. J. Cell. Biochem. 107: 697–705, 2009.

Antiproliferative effects of different plant parts of Panax notoginseng on SW480 human colorectal cancer cells.

The chemical constituents and antiproliferative effects on SW480 human colorectal cancer cells of different plant parts of P. notoginseng were evaluated. The contents of saponins in extracts from root, rhizome, flower and berry of P. notoginseng were determined using high performance liquid chromatography. The contents and proportions of saponins were different among the four plant parts. Using the cell counting method, the antiproliferative effects were evaluated and the results indicated all four extracts, at 0.05–1.0 mg/mL, showed concentration‐related antiproliferative effects on the cancer cells. The flower extract had stronger effects compared with the other three extracts; at 1.0 mg/mL, it inhibited the cell growth by 93.1% (p < 0.01). The antiproliferative effects of major saponins in notoginseng, notoginsenoside R1, ginsenosides Rb1, Rb3 and Rg1, were also evaluated, and the observed effects of major constituents support the pharmacological activities of extracts. The effects of notoginseng extracts on cell cycle and apoptosis of SW480 cells were determined using flow cytometry. Notoginseng extract can arrest the cells in S and G2/M phases. Remarkably apoptosis induction activities of notoginseng extracts were observed with the flower extract possessing the most potent effect, supporting the antiproliferative effect. Copyright

Opioid-Induced Gastrointestinal Dysfunction

Use of opioid analgesics is associated with a number of side effects, especially opioid-induced gastrointestinal dysfunction. The extensive use of these compounds and the significant negative impact of the resulting gastrointestinal dysfunction on patients’ quality of life make it an important clinical issue. In recent years our understanding of the mechanisms of opioid-induced gastrointestinal dysfunction has advanced greatly. This article reviews the underlying pathophysiological mechanisms of specific gastrointestinal adverse effects of opioids. The role of endogenous opioid peptides in certain gastrointestinal diseases is also discussed. A better understanding of the pathophysiological mechanisms of opioid-induced bowel dysfunction should lead to the development of newer opioid analgesics and improved regimens resulting in reduced gastrointestinal adverse effects.

Hydrophobic flavonoids from Scutellaria baicalensis induce colorectal cancer cell apoptosis through a mitochondrial-mediated pathway

Scutellaria baicalensis extract (SbE) has been shown to exert chemopreventive effects on several types of cancer. Baicalin, a hydrophilic flavonoid found in SbE, may have opposing effects that decrease the antitumor potential of SbE against colorectal cancer. In this study, after removing baicalin, we prepared an aglycone-rich fraction (ARF) of SbE and evaluated its anti-proliferative activity and mechanisms of action. The flavonoids found in ARF, baicalin fraction (BF) and SbE were determined by high-performance liquid chromatography (HPLC). The effects of ARF, BF, SbE and representative flavonoids on the proliferation of HCT-116 and HT-29 human colorectal cancer cells were determined by an MTS assay. The cell cycle, the expression of cyclins A and B1 and cell apoptosis were assayed using flow cytometry. Apoptosis-related gene expression was visualized by quantitative real-time polymerase chain reaction (PCR), and mitochondrial membrane potential was estimated following staining with JC-1. HPLC analysis showed that ARF contained two hydrophobic flavonoids, baicalein and wogonin, and that BF contained only baicalin. SbE had little anti-proliferative effect on the colorectal cancer cells; cancer cell growth was even observed at certain concentrations. ARF exerted potent anti-proliferative effects on the cancer cells. By contrast, BF increased cancer cell growth. ARF arrested cells in the S and G2/M phases, increased the expression of cyclins A and B1, and significantly induced cell apoptosis. Multiple genes in the mitochondrial pathway are involved in ARF-induced apoptosis, and subsequent cellular functional analysis validated the involvement of this pathway. These results suggest that removing baicalin from SbE produces an ARF that significantly inhibits the growth of colorectal cancer cells, and that the mitochondrial apoptotic pathway plays a role in hydrophobic flavonoid-induced apoptosis.