Identification and Application of Bioactive Compounds from Garcinia xanthochymus Hook. for Weed Management

Cytotoxic Isopentenyl Phloroglucinol Compounds from Garcinia xanthochymus Using LC-MS-Based Metabolomics

Many unique chemical metabolites with significant antitumor activities have been isolated from Garcinia species and have become a leading hotspot of antitumor research in recent years. The aim of this study was to identify bioactive compounds from different plant parts (leaf, branch, stem bark, fruit, and seed) of G. xanthochymus through combining LC-MS-based metabolomics with cytotoxicity assays. As a result, 70% methanol seed extract exerted significant cytotoxic effects on five human cancer cell types (HL-60, A549, SMMC-7721, MDA-MB-231, and SW480). LC-MS-based metabolomics analysis was used, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), in order to identify 12 potential markers from seed extract that may relate to bioactivity. LC-MS guidance isolated the markers to obtain three compounds and identified new isopentenyl phloroglucinols (1-3, named garxanthochin A-C), using spectroscopic methods. Among them, garxanthochin B (2) demonstrated moderate inhibitory activities against five human cancer cell types, with IC₅₀ values of 14.71~24.43 μM. These findings indicate that G. xanthochymus seed has significant cytotoxic activity against cancer cells and garxanthochin B has potential applications in the development of antitumor-led natural compounds.

Identification of four allelopathic compounds including a novel compound from Elaeocarpus floribundus Blume and determination of their allelopathic activity

Allelopathic compounds can play a vital role in protecting the environment from pollution by synthetic herbicides. Compounds isolated from plant species with allelopathic potential can be used as natural herbicides to control weeds and help reduce environmental pollution. Elaeocarpus floribundus has been reported to contain allelopathic compounds. Aqueous methanolic extracts of the leaves of this plant showed strong growth inhibitory potential against two test species (monocotyledonous Italian ryegrass and dicotyledonous alfalfa) in plants- and dose-dependent technique. Several extensive chromatographic separations of the E. floribundus leaf extracts yielded four active compounds 1, 2, 3, and 4 (novel compound). All the identified compounds showed strong growth inhibitory potential against cress. The concentrations caused for 50% growth limitation (I₅₀ values) of the cress seedlings were in the range 500.4-1913.1 μM. The findings indicate that the identified compounds might play a pivotal function in the allelopathic potential of E. floribundus tree. This report is the first on elaeocarpunone and its allelopathic potential.

Multi-Objective Optimal Design and Development of a Four-Bar Mechanism for Weed Control

Weeds compete with crops for water, nutrients, and light consequently, have adverse effects on the crop yield and overall productivity. Mechanical weeding is the most common non-chemical method for weed control, which is applied in organic farming, and the weed cultivator is the most common implement in mechanical weeding. This study aimed to design and develop an innovative active tool to optimize the cultivation depth, which can avoid damage to crop roots and improve the key performance indicators of an inter-row cultivator. A quasi-Newton optimization method and a hybrid of the non-dominated sorting genetic algorithm (NSGA-II) and goal attainment method were separately applied to synthesize and develop a four-bar mechanism for weeding requirements. The transmission angle of the mechanism and the desired path of the weeding blade were simultaneously optimized using these multi-objective optimization techniques. The performance of the developed four-bar cultivator based on the optimization techniques was compared with the ones developed based on the classic methods and also with several conventional tools evaluated in other studies. The results showed that applying the quasi-Newton optimization method and hybrid genetic algorithm can propose a more effective weed cultivator in terms of performance indicators, namely weeding performance, mechanical damage to crop plants and cultivation depth. In addition, the optimization of the transmission angle guaranteed the smooth rotations in the mechanism’s joints.

Secondary Metabolites and Their Applications

The identification of secondary metabolites present in both terrestrial and marine species continues to be a fundamental and privileged path for the emergence of new and fundamental natural products available on the market with very different applications [...]

Three Active Phytotoxic Compounds from the Leaves of Albizia richardiana (Voigt.) King and Prain for the Development of Bioherbicides to Control Weeds

The global population is increasing day by day. To meet the food demand for such a huge number of people, crop production must increase without damaging the environment, and to prevent synthetic chemical herbicides from polluting the environment, controlling weeds using bioherbicides is essential. Accordingly, using phytotoxic substances obtained from plants for biological weed management has attracted attention. The plant Albizia richardiana possesses phytotoxic compounds that have been previously recorded. Hence, we have conducted this research to characterize more phytotoxic compounds in Albizia richardiana. Aqueous methanolic extracts of Albizia richardiana plant significantly restricted the growth of the examined plants lettuce and Italian ryegrass in a species- and concentration-dependent manner. Three active phytotoxic compounds were isolated through various chromatographic methods and identified as compound 1, 2, and 3. Compound 3 exhibited stronger phytotoxic potentials than the other two compounds and significantly suppressed the growth of Lepidium sativum (cress). The concentration of the compounds required for 50% growth reduction (I₅₀ value) of the Lepidium sativum seedlings ranged between 0.0827 to 0.4133 mg/mL. The results suggest that these three phytotoxic compounds might contribute to the allelopathic potential of Albizia richardiana.