Extracts

The aim of this study was to identify possible influences of extraction methods as well as extraction parameters on the phytochemical and biological profiles of Xanthium spinosum L. extracts. Extraction methods were chosen as follows: classical methods, maceration and Soxhlet extraction; innovative extraction methods, turboextraction, ultrasound-assisted extraction, and a combination of the latter two. Extracts were subjected to total polyphenolic and flavonoid content spectrophotometric analysis. The phytochemical profile was determined for the best-yielding extracts using HPLC-MS analysis. Following the newly acquired data, another sorting of the extracts was performed. Biological activities such as antimicrobial and anti-inflammatory actions were evaluated, as well as oxidative stress reduction potential, on a Wistar rats inflammation model. Comparable results were achieved with Soxhlet extraction and ultrasound-assisted extraction, both surpassing all other tested methods in terms of yields. Bioactive compound concentrations tended to increase with the increase in extraction time and temperature. These maximal values lowered once the degradation points of the bioactive compounds were reached. Extracts demonstrated good protection against Gram-negative bacteria. Additionally, they provided good cellular protection and increased the antioxidant defense in the analyzed rat plantar tissue.

Ancient DNA extraction methods for herbarium specimens: When is it worth the effort?

PREMISE

Herbaria harbor a tremendous number of plant specimens that are rarely used for molecular systematic studies, largely due to the difficulty in extracting sufficient amounts of high-quality DNA from the preserved plant material.

METHODS

We compared the standard Qiagen DNeasy Plant Mini Kit and a specific protocol for extracting ancient DNA (aDNA) (the N-phenacylthiazolium bromide and dithiothreitol [PTB-DTT] extraction method) from two different plant genera (Xanthium and Salix). The included herbarium materials covered about two centuries of plant collections. To analyze the success of DNA extraction using each method, a subset of samples was subjected to a standard library preparation as well as target-enrichment approaches.

RESULTS

The PTB-DTT method produced a higher DNA yield of better quality than the Qiagen kit; however, extracts from the Qiagen kit over a certain DNA yield and quality threshold produced comparable sequencing results. The sequencing resulted in high proportions of endogenous reads. We were able to successfully sequence 200-year-old samples.

DISCUSSION

This method comparison revealed that, for younger specimens, DNA extraction using a standard kit might be sufficient. For old and precious herbarium specimens, aDNA extraction methods are better suited to meet the requirements for next-generation sequencing.

The first checklist of alien vascular plants of Kyrgyzstan, with new records and critical evaluation of earlier data. Contribution 1

Background

National checklists of alien plants and detailed databases of non-native plant occurrences are required to study and control regional and global plant invasions. No country in Central Asia has a national checklist of alien plants. A recent inventory counted 183 alien plant species in Kyrgyzstan, including archaeophytes and neophytes, established and casual. This preliminary checklist, which was developed for the Global Register of Introduced and Invasive Species in 2018, served as a starting point for the present study.

New information

A complete inventory of Xanthium in Kyrgyzstan has revealed that three alien species are resident in the country. Their correct nomenclature is X.orientale (syn. X.albinum, X.californicum, X.sibiricum auct.; invasive neophyle of the period of extensive grain import to the USSR after the Second World War), X.spinosum (invasive neophyte of the period of the Second World War, which arrived as a contaminant on the relocated livestock) and X.strumarium (syn. X.chinense, X.sibiricum; archaeophyte of the Neolithic period, introduced with wheat cultivation, which had lost its invasive status and appeared on the verge of extinction when its pool was no longer renewed by contaminated grain). A history of introduction to Central Asia is uncovered for all the species of Xanthium. A further spread is documented for Buniasorientalis, with a new record extending its distribution to the Eastern Tian-Shan; a complex history of its introduction to Europe and Central Asia is inferred from the archaeological data and its recent dispersal, and the pathways of its introduction to Kyrgyzstan are established. Erigeronannuus s.str. is reported as new to Kyrgyzstan and Uzbekistan, and E.lilacinus as new to Kyrgyzstan, Uzbekistan, Kazakhstan, Nepal and Tajikistan (it was previously recorded as E.annuus s.l. from the three latter countries, in which the presence of E.annuus s.str. is not confirmed). These closely related species differ in their pathways of introduction and invasion status: E.annuus s.str. is an invasive established alien which was imported as a contaminant of forage, whereas E.lilacinus is mostly a casual (locally persisting) alien introduced with contaminated seed of ornamental plants or nursery material, and also intentionally introduced and locally established in the Botanical Garden in Bishkek. Bidenstinctoria (syn. Coreopsistinctoria) is newly recorded as a casual alien from a single locality in Kyrgyzstan; this species name is validly published here in conformity with the phylogeny of Coreopsideae.

Point maps of species distributions in Kyrgyzstan are provided on the basis of a complete inventory of the literature data, herbarium specimens and documented observations, and our recent fieldwork. The maps are documented with a dataset of herbarium specimens and observations. Period and pathways of introduction, vectors of dispersal, current and historical invasion status, evidence of impact and distributional trend are established or inferred for each species. Each species is discussed in the context of plant invasions in Central Asia as a whole.

These species accounts are part of the national database of alien plants which aims at producing a comprehensive overview and analysis of plant invasions in Kyrgyzstan.

Biologically Active Constituents from Plants of the Genus Xanthium

Herbaceous annual plants of the genus Xanthium are widely distributed throughout the world and have been employed medicinally for millennia. This contribution aims to provide a systematic overview of the diverse structural classes of Xanthium secondary metabolites, as well as their pharmacological potential. On searching in various reference databases with a combination of three keywords "Xanthium", "Phytochemistry", and "Pharmacology", relevant publications have been obtained subsequently. From the 1950s to the present, phytochemical investigations have focused mainly on 15 Xanthium species, from which 300 compounds have been isolated and structurally resolved, primarily using NMR spectroscopic methodology. Xanthium constituents represent several secondary metabolite types, including simple phenols, sulfur and nitrogen-containing compounds, lignans, sterols, flavonoids, quinones, coumarins, and fatty acids, with terpenoids being the most common of these. Among the 174 terpenoids characterized, xanthanolide sesquiterpenoids are abundant, and most of the compounds isolated containing sulfur were found to be new in Nature. The ethnomedical uses of Xanthium crude extracts are supported by the in vitro and in vivo effects of their constituents, such as cytotoxicity, antioxidant, antibacterial, antifungal, antidiabetes, and hepatoprotective activities. Toxicological results suggest that Xanthium plant extracts are generally safe for use. In the future, additional phytochemical investigations, along with further assessments of the biological profiles and mechanism of action studies of the components of Xanthium species, are to be expected.

[Study on lignans from Xanthii Fructus]

This project is to investigate lignans from the dried fruits of Xanthium sibiricum (Xanthii Fructus). The chemical constituents were extract by 70% ethanol and isolated by silica gel, ODS, Sephadex LH-20, MCI column chromatography. Based on comparison of their spectral data with those reported in literature, they were elucidated as (-)-pinoresinol (1), balanophonin A (2), diospyrosin (3), dehydrodiconiferyl alcohol (4), 2-(4-hydroxy-3-methoxyphenyl)-3-(2-hydroxy-5-methoxyphenyl)-3-oxo-1-propanol (5), (-)-simulanol (6), (-)-7R,8S-dehydrodiconiferyl alcohol (7), chushizisin E (8), dihydrodehydrodiconiferyl alcohol (9), 7R,8S-dihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside (10), erythro-1,2-bis(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (11), leptolepisol D (12), 8-O-4' neolignan 4-O-β-glucopyranoside (13), (-)-1-O-β-D-glucopyranosyl-2-{2-methoxy-4-[1-(E)-propen-3-ol]phenoxyl}-propane-3-ol(14), 1-(4-hydroxy-3-methoxy)-phenyl-2-[4-(1,2,3-trihydroxypropyl)-2-methoxy]-phenoxy-1,3-propandiol (15), threo-dihydroxy dehydrodiconiferyl alcohol (16), (-)-(2R)-1-O-β-D-glucopyranosyl-2-{2-methoxy-4-[(E)-formylviny1]phenoxyl} propane-3-ol (17). Compound 2-17 were isolated from the genus Xanthium for the first time. Compound 1 were isolated form Xanthii Fructus for the first time.

The plastochron index: still useful after nearly six decades

The plastochron index (PI) introduced by Erickson and Michelini in 1957 provides a solution to a long-standing problem, of how to measure time in growing plant populations, such that the occurrence of critical developmental events can be more readily detected, compared, and analyzed, than if chronologic time is used. The PI reduces the rather large variation associated with chronologic time in measuring such events by taking advantage of the growth characteristics of stem organs that repeat at regular intervals (the plastochron) and has found widespread application in botanical research. The original formulation and derivation of the PI and associated leaf plastochron index (LPI) is reviewed. Additional formulations that have been developed to overcome some of the limitations of the original PI formulation are examined. Major advancements that have been achieved in understanding the physiology, growth, and development of agriculturally important and current model plant species are reviewed to illustrate how various researchers have used the PI in such studies. Potential uses to which the PI and LPI might be applied in emerging frontiers of plant science are suggested. A searchable bibliography of most all the primary research studies that cite the original PI article is provided.

Behavioral and electroantennogram responses of plum curculio, Conotrachelus nenuphar, to selected noxious plant extracts and insecticides

Behavioral and electroantennogram responses of plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), adults were tested for several methanolic plant extracts and organically approved insecticides. Plant extracts were evaluated for their potential as antifeedants or oviposition deterrents. These extract responses were also compared to those elicited by the non-neurotoxic, organic irritant-insecticide kaolin clay. Both sexes of plum curculio exhibited antennal response as measured by electroantennogram, which ranged from 0.2 to 1.1 mV, to plant extracts and the organic irritant/insecticide, with the greatest response to the extract of rough cocklebur, Xanthium strumarium L. (1.1 mV). No choice tests were conducted to compare feeding and oviposition by plum curculio on untreated apples or on apples treated with one of the extracts or the insecticide. The insecticide pyrethrum and extracts of X. strumarium and greater burdock, Arctium lappa L., significantly reduced feeding. Also, pyrethrum, A. lappa, Humulus lupulus L. (common hop), X. strumarium, and Verbascum songaricum Schrenk extracts completely inhibited egg deposition. In no-choice assays, the effects of kaolin clay with incorporated plant extracts on plum curculio feeding and oviposition were monitored as complementary tests. A. lappa-kaolin, H. lupulus-kaolin, and X. strumarium-kaolin mixtures significantly reduced the feeding of plum curculio compared to the control or kaolin clay alone. Each of the plant extract-kaolin mixtures evaluated, with the exception of Bifora radians Bieberstein (wild bishop), completely inhibited plum curculio oviposition as compared to controls.

The influence of photoperiod on incorporation of precursors into tocopherols and plastoquinone in Xanthium strumarium L

Radioactivity from tyrosine applied to leaves of Xanthium strumarium L. was incorporated into α- and γ-tocopherol and plastoquinone. Time-course studies on vegetative plants showed that γ-tocopherol was rapidly labelled and turned over, while α-tocopherol showed no sign of turnover. The same pattern was observed in the light and in darkness. Plastoquinone synthesis was rapid in the light but it was greatly reduced in the dark. Following floral induction the accumulation of radioactivity in γ-tocopherol was at first slower, but it later readied higher levels than in the vegetative plants. Total incorporation into α-tocopherol and plastoquinone was greatly reduced.