Allelopathic Activity of Piper sarmentosum Roxb

Influence of β-Ionone in the Phytotoxicity of the Rhizome of Iris pallida Lam

Iris pallida Lam., also known as Sweetie Iris, is a perennial ornamental and medicinal plant that produces a wide range of secondary metabolites. The Sweetie Iris was recently reported to have high allelopathic properties with the potential to be explored in sustainable weed management. This study aimed to identify and evaluate the contributions of compounds involved in the inhibitory effects of the rhizome of Sweetie Iris. High-performance liquid chromatography (HPLC) analysis was used to determine the content of β-ionone in the rhizome of Sweetie Iris. The phytotoxicity of β-ionone was evaluated on lettuce (Lactuca sativa L.) and other test plants. The content of β-ionone in the crude extract of Sweetie Iris rhizome was found to be 20.0 mg g-1 by HPLC analysis. The phytotoxicity bioassay showed that β-ionone had strong inhibitory activity on the growth of lettuce (Lactuca sativa L.) and the other test plants, including Taraxacum officinale, Stellaria media, Eleusine indica, Amaranthus hybridus, Vicia villosa, and Brassica napus. At a concentration of 23.0 µg mL-1, β-ionone inhibited the growth of all test plant species treated. Therefore, β-ionone is an active compound among the other allelopathic substances contained in the rhizome of Sweetie Iris.

Lethal and sublethal effects of essential oils fromPiper capitarianumYunck andPiper krukoffiiYunck onPlutella xylostellaL

Plutella xylostella (L.) is responsible for considerable vegetable crop losses in the metropolitan region of Manaus, Brazil. In recent decades, essential oils have been investigated as an alternative to synthetic insecticides. The genusPiperis widely distributed in Amazonia and essential oils from these plants have insecticidal properties. This study describes the chemical composition of the essential oils fromPiper capiterianumandPiper krukoffiias well as the lethal and sublethal effects onP. xylostella. The phytotoxicity of the oils on the host plant was also evaluated. Globulol was the major constituent of theP. krukoffiioil ando-cymene was the major constituent of theP. capitarianumoil. The oil fromP. capiterianumexhibited greater toxicity to larvae and eggs. This oil also presented greater repellant action, feeding deterrence and mild phytotoxicity to the host plant (Brassicae oleraceae). The findings suggest that this oil can be used in the preparation of a formulated insecticide for the management ofP. xylostellain different development phases. However, further studies are needed to evaluate the effect of this oil on crops under field conditions as well as non-target organisms and determine the cost-benefit ratio of a product formulated withP. capitarianumoil.

Recent Advances in Saffron Soil Remediation: Activated Carbon and Zeolites Effects on Allelopathic Potential

Saffron (Crocus sativus L.) is a highly valuable plant. Iran provides nearly 90% of the world’s total saffron and is the biggest global producer. The allelopathic effects of saffron corm (SC) and saffron field soil (SFS) have been hypothesized to play an important role in replanting. Recently, adsorbent materials have been used to neutralize the effects of allelochemicals. These materials, including activated carbon and zeolite, have large surface areas, pore volumes, as well as tremendous adsorptive capacity and complex chemical and physical properties. In this study, three independent experiments were conducted. In the first test, the allelopathic effects of aqueous and methanolic extracts of SC remnant and 9-year-old SFS as well as filtered aqueous extract of soil were investigated. In the second assay, the effects of SC remnants and SFS with different ages (i.e., 4, 6, and 9 years old) in combination with adsorbents were examined on the germination and growth of lettuce (Lactuca sativa L.) seedlings by the sandwich method. In the third experiment, we examined the effects of SC remnants combined with adsorbents on lettuce growth parameters. Our results showed that the allelopathic effects of aqueous and methanolic extracts of SC remnant were significantly superior to those of 9-year-old SFS. The aqueous extract of SC remnant reduced the root length of lettuce by 50%. The use of activated carbon and zeolites significantly decreased the observed allelopathic effect. Moreover, lettuce growth in rhizosphere soil was significantly inhibited by SC remnant and SFS extracts. The allelopathic effects of SC remnants caused a growth imbalance between the shoot and roots. Based on biochemical analyses, using the adsorbents increased the carotenoid content and chlorophyll index of lettuce by 23.33% and 5.25%, respectively. Adsorbents may play a role in treating soils contaminated by allelochemicals.

Phytochemical relationship of Euphorbia helioscopia and Euphorbia pulcherrima with Lactuca sativa

Allelopathy is an important phenomenon that modifies the ecosystem. A plant can enhance or reduce the growth of other plant due to the presence of a number of allelochemicals in its different parts. Euphorbia helioscopia and Euphorbia pulcherrima are medicinal plant species. Both these species are collected from wild resources for various purposes. To reduce the pressure on wild population, it is important to bring them into cultivation. Therefore, the allelopathic effects of E. helioscopia and E. pulcherrima on the growth of lettuce seeds were studied. Three different concentrations (2%, 4% and 6%) of five different solvents (methanol, acetone, ethyl acetate, n-hexane and distilled water) were used to estimate the allelopathic potential of the above-mentioned Euphorbia species. Results indicated a non-significant growth inhibitory effect of both plants on lettuce seeds. Different extracts reduced the growth of test plant to some extent but this inhibition was not significant. From the observed results, it was concluded that the studied Euphorbia species, being medicinally important crops, can be introduced as intercrop with other cash crops.

A review of the literature and latest advances in research of Piper sarmentosum

CONTEXT

Piper sarmentosum Roxb. (Piperaceae) is a traditional medicinal as well as a culinary plant in South East Asian countries, whereby aerial parts of the plant are consumed as a vegetable in various forms and the whole plant or parts are used as folk remedies, alone or in combination with other herbs, to treat various ailments. The plant has extensively been investigated in a broad range of studies to provide scientific evidence for folklore claims or to find new therapeutic uses; however, heretofore, a summary of the data are not available.

OBJECTIVE

In order to describe nutritional and therapeutic potential of P. sarmentosum and summarize scientific evidence that supports traditional claims, a literature review and latest advances in research of the plant are given herein.

MATERIALS AND METHODS

The literature has been retrieved from a number of databases such as Google Scholar, PubMed, Medline, Science Direct and SciFinder. The articles related to synthetic work, ecology and agriculture have been excluded.

RESULTS AND DISCUSSION

The review has not only revealed a number of pharmacological activities supporting the traditional claims but indicates new prospects for the plant. Antiangiogenic activity and toxicity studies suggest the usage of the plant in treating diseases involving neo-vascularization. The available efficacy, safety, pharmacokinetic and stability data urge clinical studies on extracts of the plant.

CONCLUSION

The present review may be helpful to future researchers intending to investigate the plant and natural pharmaceutical industry for preparing evidence-based formulations.