Cytotoxicity, anti-angiogenic, anti-tumor and molecular docking studies on phytochemicals isolated from Polygonum hydropiper L.

Background According to the recent global cancer statistics, breast cancer is the leading cause of deaths among women with 2.3 million new cases globally. Likewise, cervical cancer is also among the leading causes of mortality among women. Polygonum hydropiper is traditionally known for its cytotoxic effects and several bioactive cytotoxic compounds were isolated from it. This study was aimed to isolate potential anticancer compounds from its most potent fractions and evaluate their anticancer potentials. Methods Based on our earlier studies, active fractions including chloroform and ethyl acetate were subjected to column chromatography for isolation of compounds. Chemical structures of isolated compounds were confirmed via 1H NMR, 13C NMR, mass spectrometry. Purified compounds were tested for cytotoxicity against breast cancer cells (MCF-7), cervical cancer cells (HeLA) and NIH/3T3 fibroblasts cells cultures using MTT assy. Anti-angiogenic potentials of isolated compounds were evaluated via chorioallantoic membrane assay. Anti-tumor studies were done using Agrobacterium tumefaciens induced potato tumor assay. Furthermore, to understand the binding modes of Isolated compounds, molecular docking was performed against EGFR, HER2 and VEGFR using MOE as docking software. Results Two bioactive compounds PH-1 (4-methyl-5-oxo-tetrahydrofuran-3-yl acetate) and PH-2 (methyl 4-hydroxy-3-methoxybenzoate) were purified from the active fractions. In cytotoxicity studies, PH-1 exhibited highest cytotoxicity against HeLA cells with 87.50% lethality at 1 mgmL−1 concentration and LD50 of 60 µgmL−1. Likewise, PH-2 showed 82.33% cytotoxicity against HeLA cells with LD50 of 160 µgmL−1. Similarly, PH-1 and PH-2 exhibited LD50 of 170 and 380 µgmL−1 respectively. Moreover, PH-1 and PH-2 were also very potent cytotoxic compounds against NIH/3T3 cells with 81.45 and 85.55% cytotoxicity at 1 mgL−1 concentration and LD50 of 140 and 58 µgL−1 respectively. Isolated compounds exhibited considerable anti-angiogenic potentials with IC50 of 340 and 500 µgL−1 respectively for PH-1 and PH-2. In anti-tumor assay, PH-1 and PH-2 exhibited 81.15 and 76.09% inhibitions with LD50 of 340 and 550 µgL−1 respectively. Both compounds selectively binds with EGFR and HER2 receptors with low binding energies. Both compounds exhibited stronger interactions with VEGFR through binding pocket residues Lys868, Val916 and Asp1046. Conclusions Both compounds cause considerable cytotoxicity against cancer cells. The anti-angiogenic and anti-tumor results suggests additional tumor suppressive properties. Docking analysis suggests that these compound not only has the ability to bind to EGFR and HER2 but also equally binds to VEGFR and may act as potential anti-angiogenic agents.

Bio-efficacy of Plants based Formulations for the Management of Cowpea Aphid (Aphis craccivora Koch.)

Background: The cowpea (Vigna unguiculata) is damaged by various insect pests of which cowpea aphid (Aphis craccivora) causes heavy damage to the tender leaves of the plant and reduces its yield. Two plant based formulation (prepared in the Chemistry Laboratory) viz. Polygonum hydropiper floral parts and Tobacco (Nicotiana tabacum) leaf, were used for safe management. Methods: The studies were done during 2019-2020 in BCKV, Kalyani, West Bengal, India for controlling of cowpea aphid by using plant based formulation. For preparing wettable powder formulation from Polygonum hydropiper floral parts and tobacco leaf the different ingredients are required viz. china clay, silica gel, wetting agent, dispersing agent etc. Physico-chemical analysis was done for preparation of accurate Wettable Powder formulation. Result: Cowpea aphid causes damage the tender leaves of the plant. It was revealed that imidacloprid (Confidor 17.8 SL) @ 1.0 ml/3L was found the most effective treatment against aphids giving more than 80% control followed by tobacco leaf (50 WP) @ 8 g/L of water (more than 70% control), fipronil (Regent 5% SC) @ 2.5 ml/L of water and Polygonum floral parts (50 WP) @ 8 g/L of water (more than 65% control both). The quality parameters of WP (50%) formulation was satisfactory as per the FAO specifications in terms of wet sieved test, wettability, foaming and suspensibility performed on the 0-day and also after 15th day at room temperature, at 65°C and at freezing temperature conditions.

Toxic Effects of Vitex Negundo L. And Polygonum Hydropiper L. Plant Extract Treated Fishes on Rats

An observation was made to taste the toxic effect of Vitex negundo L. and Polygonum hydropiper L. (leaf and bark) plants extracts treated fish fed group on rats, Bandicota indica. Six group of rats were fed on two different kinds of plants extracts, one is radiation dose and another untreated control group. These were, the untreated control group rats were feed on normal food such as dried fish and wheat whereas treated rats were given plant extracts and radiation dose treated by dried fish. The experimental rats were fed of 4 ml dose of plant extracts in 70% ethyl alcohol (ratio 1:10) and 4 kGy radiation treated dry fish. The toxic properties of these plant extracts were carried out the vital organs of liver, kidney, stomach, spleens, lungs and muscles on male rats .The lower mammalian species rats were used for preliminary survey their body weight gained and histopathological changes were observed. The experiment was carried out from August 2004 to December 2004. Initially the concentration of rats body weights were found as, control group (C) 43 g/m, Vitex negundo leaf treated fish fed group of rat (VL) 44.8 g/m, Vitex negundo bark treated fish fed group of rat (VB) 44.4 g/m, Polygonum hydropiper leaf treated fish fed group of rat (PL) 46.2 g/m, Polygonum hydropiper bark treated fish fed group of rat (PB) 47.8 g/m and radiation treated fish fed group of rat (R) 47 g/m. After 30 days the weight gain of rats recorded as, group (C) 324.6 g/m, (VL) 357.2 g/m, (VB) 362 g/m, (PL) 342 g/m, (PB) 323.6 g/m and (R) 352 g/m and 90 days after the body weight were group (C) 727.2 g/m, (VL) 781.2 g/m, (VB) 795.8 g/m, (PL) 780.4 g/m, (PB)764.8 g/m and R 789.8 g/m respectively. The present study is, the first attempt to use the rats body weight data found well and most suitable 4ml dose of V. negundo bark treated extracts than leaf treated group and 4 kGy radiation group. Histopathological changes of rats organs test liver was well preserved, kidney-the glomeruli, tubules, blood vessel were showed no significant changes, in the stomach-the mucosa, sub mucosa were well, in the spleen-red and white pulp were showed no significant changes, lung-the alveoli was good and in the muscle-the skeletal muscle were remain unaltered. Bangladesh J. Zool. 49(1): 125-135, 2021

Community Trait Responses of Three Dominant Macrophytes to Variations in Flooding During 2011–2019 in a Yangtze River-Connected Floodplain Wetland (Dongting Lake, China)

In lacustrine wetlands connected to rivers, the changes in flood regimes caused by hydrological projects lead to changes in the community traits of dominant macrophytes and, consequently, influence the structure and function of wetland vegetation. However, community trait responses of macrophytes to the timing and duration of flood disturbance have been rarely quantified. In 2011–2019, we investigated plant species diversity, density, and biomass in three dominant macrophyte communities (Carex brevicuspis C.B. Clarke, Miscanthus sacchariflorus (Maxim.) Hackel, and Polygonum hydropiper L.) through monthly field surveys in Dongting Lake wetlands. Partial least squares regressions were used to analyze how the variations in hydrological regimes affected plant community traits. Apparent inter-annual fluctuations in plant community traits were detected during 2011–2019. The species richness and Shannon index of diversity of Miscanthus and Polygonum communities increased, whereas the Shannon index of diversity of Carex community decreased. Variation in flooding had a greater effect on Polygonum and Carex community traits than on Miscanthus community traits. Flooding disturbed all plant communities, especially when the duration and timing varied. Shorter inundation periods caused the biomass of Miscanthus community to decline, and that of Carex and Polygonum communities to increase. Earlier flood recession caused the species richness and Shannon index of diversity of Polygonum and Miscanthus community to increase, and those of Carex community to decrease. These findings imply that shorter inundation durations and earlier flood recession generated by the operation of the Three Gorges Dam have changed the macrophyte growth pattern.

Interacting Flooding and Competition Negatively Affect Growth of Riparian Species Dominating a Reservoir Shoreline

Plant–plant interactions change in response to environmental conditions, and riparian species are commonly influenced by flooding. This study tested whether flooding affects the intraspecific and interspecific competition of two riparian species and whether such effects depend on the topographic positions where plants have established. Seeds of the riparian species Polygonum hydropiper were collected from both low and high positions within the shoreline of the Three Gorges Reservoir. Groups of P. hydropiper seedlings from each position were either grown alone (i.e., without competition), with another group of P. hydropiper seedlings (i.e., intraspecific competition), or with a group of seedlings of the companion species Xanthium sibiricum (i.e., interspecific competition). Each group comprised six replicates. In total, 288 plants of P. hydropiper and 84 plants of X. sibiricum were selected for the experiment. Seedlings were subjected to control and flooding treatments for 60 days. Irrespective of competition type (i.e., intra- or interspecific), both flooding and competition negatively affected the growth and/or photosynthetic capacities of P. hydropiper. Flooding only interacted with competition to explain total biomass. Flooding reduced total biomass in a larger proportion in the absence of competition, and, to a lesser extent, with intraspecific competition, compared to interspecific competition. However, such interaction effects were independent of the positions where the seeds that originated from the plants were collected from. Interspecific competition significantly decreased the chlorophyll content and photosynthetic efficiency of plants, while intraspecific competition did not. In general, plants from lower positions had higher total chlorophyll content than plants from higher positions. These results suggest that flooding may regulate the population dynamics of P. hydropiper by altering its competitive interactions.

Predicting the effects of reservoir impoundment on phytoplankton and shoreline vegetation communities using the space-time substitution method

The prediction of the influence of reservoir impoundment on water quality and phytoplankton community is the basis of ecological compensation or restoration. The aim of the current study was to predict the effects of reservoir impoundment on phytoplankton and shoreline vegetation communities using the space-time substitution method. The Huangjinxia Reservoir under construction on the Han River was selected as the research object. The space-time substitution method indicated that the average values of the total phosphorus (TP) and ammonia (NH4+-N) increased from 0.049 and 0.279 mg L−1 to 0.139 and 1.132 mg L−1, respectively, after reservoir impoundment. The percentage of diatom biomass exceeded 95% before the reservoir impoundment. However, it was gradually decreased to 75% after the reservoir impoundment. Meanwhile, the biomass of Chlorophyta, Cryptophyta and Pyrrophyta increased significantly, accounting for 32, 20 and 13% of the total biomass, respectively, after reservoir impoundment. Cynodon dactylon (65.3%), Polygonum hydropiper (51.7%) and Aster subulatus (50.3%) were the dominant shoreline vegetation before the reservoir impoundment, whereas after the reservoir impoundment, the dominant species shifted to Alternanthera philoxeroides (62.3%), Lobelia chinensis (55.7%) and C. dactylon (53.9%). Our results suggested that the percentage of bloom-forming phytoplankton would gradually increase after the reservoir impoundment. In addition, A. philoxeroides, C. dactylon and L. chinensis would be the plants suitable for living in the shoreline of reservoirs in this area.