The historical trajectory of Chenopodiaceae research in Bulgaria begins in the late nineteenth century, when pioneering botanists including Bornmüller, Georgiev, Yavashev, Toshev and Urumov published the first distribution records. These scattered observations were consolidated by Velenovský in his two editions of Flora bulgarica. The first edition, published in 1891, listed 28 Chenopodiaceae species belonging to 9 genera, including 12 species of Chenopodium, 4 of Atriplex, 4 of Kochia, 2 of Camphorosma and 2 of Suaeda. The second edition of 1898 added new distribution data, bringing the total number of species reported for Bulgaria in the nineteenth century to 32. These early accounts established the foundation for all subsequent floristic work in the country and documented the presence of familiar species such as Chenopodium album, C. rubrum, C. glaucum and C. murale, alongside halophytic representatives like Salicornia herbacea and Salsola kali.

The twentieth century witnessed a steady expansion of knowledge about the Bulgarian Chenopodiaceae. In the first two decades, the main sources of information were the prolific works of Urumov, Kovachev, Davidov, Neichev, Petkov, Stranski and Yordanov. This accumulated chorological data was summarized in the first edition of Flora of Bulgaria in 1924, where the family was presented by 44 species and 13 genera. The second edition of 1933 reported 39 species, with five species removed from the first edition, including Camphorosma ruthenicum and Corispermum canescens. The third edition of 1948 listed 41 species and added two new species to the Bulgarian flora: Chenopodium opulifolium, mentioned as a widely spread ruderal plant, and Corispermum hyssopifolium, discovered on the sands of Danubian islands in the Belene group. The fourth edition of 1966 introduced one new genus and species for Bulgaria, Ceratocarpus arenarius.

The most exhaustive treatment of the family came with Yordanov and colleagues in Flora of the People’s Republic of Bulgaria, which reported a total of 48 Chenopodiaceae species belonging to 15 genera. This monumental work included 4 cultivated species—Atriplex hortensis, Spinacia oleracea, Beta vulgaris and Kochia scoparia—and documented Chenopodium ambrosioides as a new species for the country, reported for the first time from the sands near Varna and the experimental field in Ovcha Kupel. Subsequent floristic reports throughout the 1970s and 1980s supplemented this data. The Field Guide to the vascular plants in Bulgaria of 1992 represented the family by 48 species across 14 genera, noting that the distribution of Bassia sedoides had not been confirmed and adding new records including Chenopodium chenopodioides from the Northern Black Sea coast and two new Atriplex species, A. micrantha and A. halimus.

The new millennium brought further refinements and discoveries. Delipavlov and Cheshmedzhiev listed 50 species for the family in 2011, while the Conspectus of the Bulgarian vascular flora by Assyov and Petrova registered 50 species across 13 genera, including one new species for the country, Chenopodium schraderianum. Five Chenopodiaceae species are protected by the Biological Diversity Act of 2007: Bassia hirsuta, Halimione pedunculata, H. portulacoides, Petrosimonia brachiata and Suaeda heterophylla. The Red Data Book of the Republic of Bulgaria includes 4 species, with B. hirsuta and Corispermum marschalii referred to the IUCN category EN (endangered), whereas P. brachiata and S. heterophylla are assessed as CE (critically endangered). These annual halophyte communities are among the protected natural habitats pursuant to Directive 92/43/EEC and are classified as an endangered habitat in the Red Data Book.

The last decade has seen the genus Chenopodium undergo substantial taxonomic revision driven by molecular phylogenetic studies. Grozeva reported a new species for the country, Chenopodium pumilio, in 2007, and subsequently suggested that C. acuminatum be deleted from the Bulgarian flora as incorrectly identified. Six new species and one subspecies from the genus Chenopodium—C. strictum, C. striatiforme, C. album subsp. pedunculare, C. pratericola, C. probstii and C. missouriense—have been reported for the Bulgarian flora. The fourth edition of the Conspectus of Bulgarian vascular flora in 2012 listed 56 species across 14 genera. The Euro+Med Plant Base reported 53 species and 19 genera for Bulgaria, reflecting the modern circumscription of Chenopodium sensu stricto, which now excludes genera such as Blitum, Chenopodiastrum, Dysphania, Lipandra and Oxybasis that were formerly included within Chenopodium sensu lato. According to the most recent data, the family is represented in Bulgarian flora by 51 species and 2 subspecies.

Morphological studies on Bulgarian Chenopodiaceae have concentrated primarily on Chenopodium sensu lato. Detailed investigations have covered Chenopodium album and Dysphania botrys from 18 populations, Blitum bonus-henricus from 10 populations with ecological notes, C. pratericola, the genus Dysphania, C. probstii and C. missouriense, and Blitum virgatum. Further taxa studied include Bassia hirsuta and Petrosimonia brachiata. These morphological analyses have provided essential baseline data for understanding the variation within and between Bulgarian populations, contributing to more accurate species identification and taxonomic decisions.

Karyological research has been equally productive, beginning with Markova’s 1968 study on Dysphania multifida, which revealed a tetraploid chromosome number of 2n = 36. Subsequent investigations by Kožuharov and Kuzmanov, Cheshmedzhiev, Popova and Ceschmedjiev, and Van Loon and Van Setten established chromosome numbers for additional species. Grozeva and Stoeva published chromosome numbers for the first time for 4 species in 2006, and Grozeva reported first-time chromosome numbers for 8 species in 2007, 7 species in 2010, and additional species in subsequent years. For the members of the family from Bulgarian populations, diploid (2n = 16, 18), tetraploid (2n = 32, 36) and hexaploid (2n = 54) chromosome numbers have been found, with two types of chromosomes—metacentric and submetacentric. Basic chromosome numbers x = 9 and x = 8 have been registered, with diploid species being dominant. According to Petrova and Vladimirov, 80.4% of the Chenopodiaceae species have been studied karyologically, though data remains lacking for Beta vulgaris subsp. maritima, Camphorosma annua, C. monspeliaca, Ceratocarpus arenarius, Halimione pedunculata, H. portulacoides, Polycnemum arvense, P. heuffelii, P. majus and Spinacia oleracea from Bulgarian populations.

Phytochemical investigations have revealed an extraordinary chemical arsenal within the Bulgarian Chenopodiaceae. According to the Medicinal Plants Act of 2000, 11 species are considered medicinal plants, including Atriplex rosea, Blitum bonus-henricus, B. virgatum, Camphorosma monspeliaca, Chenopodium album subsp. album, C. vulvaria, Dysphania botrys, Lipandra polysperma, Oxybasis rubra, Salicornia europaea and Salsola tragus. The chenopods contain minerals, primary metabolites such as carbohydrates, amino acids and proteins, as well as secondary metabolites including flavonoids, saponins, terpenes, sterols, alkaloids and vitamins. The aerial parts of Blitum bonus-henricus are a rich source of bioactive compounds, with 36 compounds distinguished, including 22 saponins of 8 sapogenins, 12 flavonoid glycosides and 2 ecdysteroids. The flavonoid and saponin-rich fractions showed in vitro hepatoprotective and antioxidant activity comparable to those of the flavonoid complex silymarin in a model of metabolic bioactivation induced by carbon tetrachloride. Nine flavonol glycosides of patuletin, 6-methoxykaempferol and spinacetin were reported to reduce lipid damage, showed antioxidant, neuroprotective, anti-α-glucosidase and lipase activities, and possessed no toxicity on the HepG2 cell line.

The phytochemical profile of Blitum virgatum is equally impressive, with preliminary screening showing the presence of carbohydrates, flavonoids, phytosterols, saponins and alkaloids. The main secondary metabolites include terpenes such as limonene, α-terpinene, β-phellandrene, carvacrol, thymol, α-pinene, β-pinene, camphor and β-caryophyllene, alongside the oleanane triterpene 30-normedicagenic acid. New flavonol glycosides detected include 6-methoxykaempferol-3-O-β-gentiobioside, gomphrenol-3-O-β-gentiobioside and gomphrenol-3-O-[6-O-(β-D-glucopyranosyl)-β-D-glucopyranoside], as well as known compounds patuletin-3-O-β-gentiobioside and spinacetin-3-O-β-gentiobioside. The highest radical-scavenging activity evaluated by DPPH and ABTS methods was shown by patuletin-3-O-β-gentiobioside and 6-methoxykaempferol-3-O-β-gentiobioside, comparable with those of the classic antioxidant ascorbic acid. A newly identified acylated flavonol triglycoside, gomphrenol-3-O-(5”’-O-E-feruloyl)-β-D-apiofuranosyl-(1→2)[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranoside, demonstrated the ability to reduce damage caused by the hepatotoxic agent carbon tetrachloride and preserve cell viability and glutathione levels. These findings position the Bulgarian Chenopodiaceae as a promising source of safe hepatoprotective agents, with the glycosides of phytolaccagenin, bayogenin and medicagenic acid representing a particularly valuable class of bioactive compounds. The systematic review of this family not only consolidates over a century of botanical research but also illuminates the extraordinary potential of these humble ruderal and halophytic plants for future pharmacological and conservation science.

Subject of Research: A review of taxonomic, chorological, morphological, karyological and phytochemical studies on the Bulgarian members of the family Chenopodiaceae.

Article Title: Studies on the Bulgarian members of the family Chenopodiaceae s. stricto : a review

Article References: Boneva, V. S., & Petkova, N. T. (2022). Studies on the Bulgarian members of the family Chenopodiaceae s. stricto: a review. BioRisk, 18, 17-34. https://doi.org/10.3897/biorisk.18.78548

Image Credits: AI Generated

DOI: 10.3897/biorisk.18.78548

Keywords: Chenopodiaceae, Bulgaria, taxonomy, halophytes, phytochemistry, karyology, Chenopodium, floristics, Studies, Bulgarian, members, family