Putative Identification of New Phragmaline-Type Limonoids from the Leaves of Swietenia macrophylla King: A Case Study Using Mass Spectrometry-Based Molecular Networking.

Swietenia macrophylla King is a plant commonly known as Brazilian mahogany. The wood from its stem is highly prized for its exceptional quality, while its leaves are valued for their high content of phragmalin-type limonoids, a subclass of compounds known for their significant biological activities, including antimalarial, antitumor, antiviral, and anti-inflammatory properties. In this context, twelve isolated limonoids from S. macrophylla leaves were employed as standards in mass spectrometry-based molecular networking to unveil new potential mass spectrometry signatures for phragmalin-type limonoids. Consequently, ultra-performance liquid chromatography coupled with high-resolution mass spectrometry was utilized for data acquisition. Subsequently, the obtained data were analyzed using the Global Natural Products Social Molecular Networking platform based on spectral similarity. In summary, this study identified 24 new putative phragmalin-type limonoids for the first time in S. macrophylla. These compounds may prove valuable in guiding future drug development efforts, leveraging the already established biological activities associated with limonoids.

Acridone Alkaloids from Swinglea glutinosa (Rutaceae) and Their Effects on Photosynthesis.

Continuing our search for herbicide models based on natural products, we investigated the action mechanisms of five alkaloids isolated from Swinglea glutinosa (Rutaceae): Citrusinine-I (1), glycocitrine-IV (2), 1,3,5-trihydroxy-10-methyl- 2,8-bis(3-methylbut-2-en-1-yl)-9(10H)-acridinone (3), (2R)-2-tert-butyl-3,10-dihydro-4,9-dihydroxy-11-methoxy-10-methylfuro[3,2-b]acridin-5(2H)-one (4), and (3R)-2,3,4,7-tetrahydro-3,5,8-trihydroxy-6-methoxy-2,2,7-trimethyl-12H-pyrano[2,3-a]acridin-12-one (5) on several photosynthetic activities in an attempt to find new compounds that affect photosynthesis. Through polarographic techniques, the compounds inhibited the non-cyclic electron transport in the basal, phosphorylating, and uncoupled conditions from H2 O to methylviologen (=MV). Therefore, they act as Hill reaction inhibitors. This approach still suggested that the compounds 4 and 5 had their interaction site located at photosystem I. Studies on fluorescence of chlorophyll a suggested that acridones (1-3) have different modes of interaction and inhibition sites on the photosystem II electron transport chain.

Potential insecticidal activity of aminonaphthoquinone Mannich bases derived from lawsone and their copper (II) complex derivatives.

The fall armyworm, Spodoptera frugiperda, is a polyphagous pest that causes important damage in different regions of America and mainly affects corn crops in both tropical and subtropical areas. Currently, control relies on both transgenic plants and/or chemical pesticides. In this work, we describe insecticidal activity against the fall armyworm from a series of Mannich bases (1-10), derived from 2-hydroxy-1,4-naphthoquinone (lawsone), substituted benzaldehydes, and two primary amines, and their Cu2+ complexes (11-20). The [Cu(L)2] complexes were more effective in larval mortality compared to the free Mannich bases. Among the tested compounds, complex 11 showed the highest toxicity, with 70.00% larval mortality.

Effects of limonoids from Cipadessa fruticosa on fall armyworm.

Six mexicanolide limonoids isolated from the dichloromethane extract of the fruits of Cipadessa fruticosa Blume (Meliaceae) were evaluated against Spodoptera frugiperda (J. E. Smith). Gedunin was used as a positive control. When incorporated into an artificial diet of neonates at 50.0 mg kg(-1), febrifugin A showed 73.3% mortality. All the compounds showed moderate insecticidal activity, except for ruageanin A, when compared with the control. Febrifugin also showed growth inhibition and antifeedant activities (at 100.0 mg kg(-1)). The correlation between the insecticidal activity of the isolated compounds and their chemical structure was discussed.

Compounds from Vitex polygama active against kidney diseases.

Vitex polygama Cham. (Lamiaceae, formerly Verbenaceae) is a familiar Brazilian species popularly known as Tarumã whose leaf tea has been used by population to treat kidney diseases. The aim of this research was to investigate the hydroalcoholic extract of leaves in order to isolate the active compounds. Hydroalcoholic extract of leaves was obtained by stirring the previous hexane and methanol extracted leaves residue with 50% aqueous MeOH solution by ultra-sonic mixing. The obtained extract was partitioned with n-butanol. The yielded fraction was subsequently submitted to several chromatographic procedures to lead to the isolation of O-glycosidicflavones orientin and isoorientin as well as C-glycosylflavones schaftoside and carlinoside along with their isomers, known as potent anti-inflammatory, antinociceptive and antioxidant agents, then identified as the active constituents, justifying the folk use of the plant to combat and prevent kidney stone and inflammation.

Enzymatic inhibitory activity and trypanocidal effects of extracts and compounds from Siphoneugena densiflora O. Berg and Vitex polygama Cham.

Hexanic, methanolic, and hydroalcoholic extracts, and 34 isolated compounds from Vitex polygama Cham. (Lamiaceae, formely Verbenaceae) and Siphoneugena densiflora O. Berg (Myrtaceae) were screened for their trypanocidal effects on bloodstream forms of Trypanosoma cruzi and T brucei, as well as for their enzymatic inhibitory activities on glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) and trypanothione reductase (TR) enzymes from T cruzi and adeninephosphoribosyl transferase (APRT) enzyme from Leishmania tarentolae. In general, polar extracts displayed strong effects and some of the tested compounds have shown good results in comparison to positive controls of the bioassays.

A biosynthetic pathway of sesquiterpene lactones in Smallanthus sonchifolius and their localization in leaf tissues by MALDI imaging.

The biosynthetic route for epoxyangelate esters of the sesquiterpene lactones (STL) uvedalin and enhydrin from in vitro cultures of Smallanthus sonchifolius (Asteraceae) was investigated with (13)C-precursors for the first time in the literature. Photomicroscope analyses and studies using MALDI-MS imaging confirmed that glandular trichomes accumulate STL.

Effects of limonoid cedrelone on MDA-MB-231 breast tumor cells in vitro.

Cancer is the second leading cause of death, preceded only by cardiovascular diseases, and there is epidemiological evidence that demonstrate this tendency is emerging worldwide. Brazil has an extensive vegetal biodiversity with more than 55,000 species listed. Such biodiversity collaborates with the finding of compounds which could be the basis for the design of new anti-tumor drugs, with fewer side effects than the conventional chemotherapy used currently. Cedrelone is a limonoid isolated from Trichilia catigua (Meliaceae) which is a native Brazilian plant. This study demonstrates that cedrelone inhibits proliferation, adhesion, migration and invasion of breast tumor cells from the line MDA-MB-231. The effects of cell migration and invasion on MDA-MB-231 cell may be explained, at least in part, by the ability of cedrelone to inhibit MMP activity. We also demonstrate that cedrelone is able to induce apoptosis in MDA-MB-231 cells. There are only a few works investigating the effect of limonoids in cellular processes closely related to tumor progression such as adhesion, migration and invasion. To the best of our knowledge, this is the first work describing the effects of a limonoid on tumor and non-tumor cell adhesion process.

Cyclopropane- and spirolimonoids and related compounds from Hortia oreadica.

The dichloromethane extract from taproots of Hortia oreadica afforded six limonoids, these are 9,11-dehydro-12α-acetoxyhortiolide A, hortiolide C, 11α-acetoxy-15-deoxy-6-hydroxyhortiolide C, hortiolide D, hortiolide E, 12ß-hydroxyhortiolide E, in addition to the known limonoid, guyanin. The dichloromethane extract from stems of H. oreadica also afforded two limonoids 9,11-dehydro-12α-hydroxyhortiolide A and 6-hydroxyhortiolide C. As a result of this study and literature data, Hortia has been shown to produce highly specialized limonoids that are similar to those from the Flindersia (Flindersioideae). The taxonomy of Hortia has been debatable, with most authors placing it in the Toddalioideae. Considering the complexity of the isolated limonoids, Hortia does not show any close affinity to the genera of Toddalioideae. That is, the limonoids appear to be of little value in resolving the taxonomic situation of Hortia.