Some
Lathyrus species have the potential for human consumption due to various attributes such as edibility and medicinal effects. Therefore, in this study, the chemical compositions and certain heavy metal contents of the aerial parts of
L. annuus,
L. hierosolymitanus,
L. hirsutus,
L. undulatus,
L. tuberosus and tubers of
L. tuberosus (Fig 3) were investigated.
The findings are showcased comparatively in Table 2. All elements in Table 2 are heavy metals except Na, Mg, K and Ca. Among the investigated metals, the highest amounts of Ca, Mn, Cd, Zn and Cu were found in
L. hirsutus; Na and Fe in
L. hierosolymitanus; Mg in
L. annuus; and K in
L. tuberosus. The lowest amounts of K, Na, Fe and Mg were found in
L. hirsutus; Ca in
L. tuberosus (tb.); Zn in
L. tuberosus; Mn in
L. tuberosus and tubers of
L. tuberosus. In all samples, the amounts of Cr and Ni were below 0.008 and 0.006 ppm, respectively. Cd and Cu levels were below 0.005 and 0.003 ppm, respectively, in all species except
L. hirsutus. Zn was not detected in
L. undulatus.
Although metals with a density of greater than 5 g/cm
3 are generally classified to as heavy metals, in medicine, metals with toxic properties are defined as heavy metals, regardless of their density. While Fe, Cu, Zn and Ni are essential at certain levels in living organisms, they exert toxic effects when their concentrations exceed 1-10 ppm. Some non-essential heavy metals, particularly Cd, Hg and Pb, can be toxic even at trace levels ranging from 0.001-0.1 ppm (
Özbolat and Tuli, 2016). Heavy metals such as Cr, Cu, Fe, Cd, Zn, Ni, As and Pb can cause organ dysfunction even at low concentrations within the human body
(Ohiagu et al., 2022). The accumulation of heavy metals in plants and their subsequent entry into the food chain pose a serious threat not only to the environment but also to human health
(Khan et al., 2017; Ansari et al., 2024).
The species whose chemical composition and some heavy metal contents were examined in the current study are utilised by humans for various purposes, including medicinal properties and nutritional values.
The seeds of
L. annuus and the raw form of
L. tuberosus are used as food. The tubers of
L. tuberosus are consumed raw, roasted, or boiled for both nutritional and medicinal purposes, particularly in the treatment of diarrhoea.
L. hierosolymitanus is used medicinally for the treatment of obesity and overweight.
L. undulatus serves medicinal purposes, specifically in reducing stomach cancer risk and is also used as fodder. Finally,
L. hirsutus is utilised for fodder and forage (
Hossaert-Palauqui and Delbos, 1983;
Baytop, 1984;
Yıldırım et al., 2001; Özkan, 2011;
Kızılarslan and Özhatay, 2012;
Jaradat et al., 2017; Smýkal,and Erdõs, 2020;
Sakinoğlu-Oruç et al., 2021;
Ramya et al., 2022).
The chemical compositions of several
Lathyrus species have been characterised in previous studies. The seeds of
L. tefennicus H.Genç & A.Þahin and
L. egirdiricus H.Genç & A.Þahin, as well as the aerial parts of
L. phaselitanus Hub.-Mor. & Davis,
L. lycicus Boiss. and
L. belinensis N.Maxted & D.J.Goyder, were examined in these studies. A summary of the literature data is presented in Table 3.
Soil and plants near highways are exposed to Cd and Mn contamination resulting from motor vehicle exhaust and tire wear
(Lytle et al., 1995; Öktüren-Asri et al., 2007). Mn toxicity affects the nervous system (
Mahurpawar, 2015), whereas Itai-itai disease, a form of Cd poisoning, manifests with various symptoms including osteomalacia, renal anaemia and tubular nephropathy
(Ohiagu et al., 2022). When the investigated species are compared with each other and with data from the literature, certain element concentrations stand out. Considering heavy metals known to cause toxicity,
L. hirsutus exhibited relatively high levels of Mn and Cd, one of the most toxic heavy metals, according to literature data. Cd has not been detected in any of the species reported in the literature. The collection locality of the
L. hirsutus is located near a road. It should be noted that the high Cd and Mn concentrations in this species may have been affected by environmental factors. Cd contents of the other species were lower than 0.005 ppm. Mn contents of the aerial parts and tb. of
L. tuberosus were lower than 0.002 ppm. Mn levels of
L. hierosolymitanus and
L. annuus were 17 and 21 mg/kg, respectively and compatible with the literature.
Nausea, vomiting and diarrhoea are symptoms of Cu poisoning and increased exposure leads to pathological changes in multiple tissues, particularly the liver and kidneys. Increased absorption from the intestine leads to the development of Wilson’s disease (
Özbolat and Tuli, 2016). The Cu content in
L. hirsutus is several times higher than the values reported in the literature, whereas it is below 0.003 ppm in the other species.
Zn (II) oxide adversely affects the gastrointestinal system, causing symptoms such as nausea, vomiting and abdominal pain. Excessive Zn accumulation within cells triggers cell death
(Ohiagu et al., 2022). Zn concentrations in
L. hirsutus,
L. hierosolymitanus and the tb. of
L. tuberosus were relatively consistent with values reported in the literature. Zn levels in
L. annuus and
L. tuberosus were considerably lower than those reported in the literature. Zn was not detected in
L. undulatus.
High accumulation of Ni and its compounds may cause various types of cancer, lung fibrosis, as well as kidney and cardiovascular infections, whereas exposure to elevated levels of Cr is toxic and carcinogenic to humans (
Mahurpawar, 2015;
Ohiagu et al., 2022). Ni and Cr concentrations were found to be below 0.008 ppm in all examined species, whereas literature reports indicate that these metals were not determined in
L. tefennicus,
L. egirdiricus,
L. phaselitanus,
L. lycicus and
L. belinensis.
The highest Fe concentrations were found in
L. hierosolymitanus (229 mg/kg) and the tb. of
L. tuberosus (80 mg/kg). The Fe contents in the other species were determined to be lower than those reported in the literature. The K contents of
L. tuberosus,
L. undulatus,
L. annuus and
L. hierosolymitanus, as well as the Ca contents of all species, were found to be higher than those reported in the literature.
L. hirsutus contains very low levels of Na, Mg and Fe.
Element concentrations in plants are known to depend on the amount of the element in the soil, the plant’s uptake efficiency, species-specific characteristics and the plant’s ability to transport elements through its vascular tissues
(Viers et al., 2013). Different element concentrations were observed even in different parts of the same plant, such as the aerial parts and tb. of
L. tuberosus. These differences were more pronounced in the concentrations of Na, K and Zn. The significantly higher levels of Mn, Cd and Cu in
L. hirsutus compared to the other species may be attributed to the environmental conditions of its habitat. Since the collection locality of this species is in close proximity to a road, exhaust emissions may have affected the environment.
The samples of the species examined in this study were collected from different localities and habitats. The soil composition and climatic conditions of these regions may also have affected their elemental profiles. Considering that the element concentrations may also vary according to the plant species, it can be thought that it is normal for the results obtained in the species studied in the current study to show differences from each other and the literature. However, further research is required to clarify whether the elevated heavy metal contents of the species are attributable to environmental conditions or inherent species-specific characteristics.
