The plant exposures are one of the most frequent poisonings reported to poison control centres. The diagnosis of intoxicated patients is usually based on the morphological analysis of ingested plant portions; this procedure requires experience in systematic botany, because the plant identification is based on few evident traits. The objective of this research is to test DNA barcoding approach as a new universal tool to identify toxic plants univocally and rapidly. Five DNA barcode regions were evaluated: three cpDNA sequences (trnH-psbA, rpoB and matK) and two nuclear regions (At103 and sqd1). The performance of these markers was evaluated in three plant groups: (1) a large collection of angiosperms containing different toxic substances, (2) congeneric species showing different degrees of toxicity and (3) congeneric edible and poisonous plants. Based on assessments of PCR, sequence quality and resolution power in species discrimination, we recommend the combination of plastidial and nuclear markers to identify toxic plants. Concerning plastidial markers, matK and trnH-psbA showed consistent genetic variability. However, in agreement with CBOL Plant Working Group, we selected matK as the best marker, because trnH-psbA showed some problems in sequences sizes and alignments. As a final and relevant observation, we also propose the combination of matK with a nuclear marker such as At103 to distinguish toxic hybrids form parental species. In conclusion, our data support the claim that DNA barcoding is a powerful tool for poisonous plant identifications.

/pdf/identification-of-poisonous-plants-by-dna-barcoding-approach-279h3osw4s.pdf

Identification of poisonous plants by DNA barcoding approach

The plant exposures are one of the most frequent poisonings reported to poison control centres. The diagnosis of intoxicated patients is usually based on the morphological analysis of ingested plant portions; this procedure requires experience in systematic botany, because the plant identification is based on few evident traits. The objective of this research is to test DNA barcoding approach as a new universal tool to identify toxic plants univocally and rapidly. Five DNA barcode regions were evaluated: three cpDNA sequences (trnH-psbA, rpoB and matK) and two nuclear regions (At103 and sqd1). The performance of these markers was evaluated in three plant groups: (1) a large collection of angiosperms containing different toxic substances, (2) congeneric species showing different degrees of toxicity and (3) congeneric edible and poisonous plants. Based on assessments of PCR, sequence quality and resolution power in species discrimination, we recommend the combination of plastidial and nuclear markers to identify toxic plants. Concerning plastidial markers, matK and trnH-psbA showed consistent genetic variability. However, in agreement with CBOL Plant Working Group, we selected matK as the best marker, because trnH-psbA showed some problems in sequences, sizes and alignments. As a final and relevant observation, we also propose the combination of matK with a nuclear marker such as At103 to distinguish toxic hybrids form parental species. In conclusion, our data support the claim that DNA barcoding is a powerful tool for poisonous plant identifications.

Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial activity of five Commelinaceae methanolic leaf extracts. The antioxidant content was evaluated by the total phenolic content (TPC), total tannin content (TTC), and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH free radical scavenging (FRS), ferric reducing power (FRP), and ferrous ion chelating (FIC); of the five plants, the methanolic leaf extract of Tradescantia zebrina showed the highest antioxidant content and activity, and exhibited antibacterial activity against six species of Gram-positive and two species of Gram-negative bacteria in a range of 5-10 mg/mL based on the broth microdilution method.

https://www.mdpi.com/2076-3921/3/4/758/pdf

Antioxidant Content, Antioxidant Activity, and Antibacterial Activity of Five Plants from the Commelinaceae Family

Tannins, saponins and calcium oxalate crystals from Nigerian species of Boerhavia L. (Nyctaginaceae)

Histochemical Studies on Some Nigerian Species of Vigna Savi (Leguminisae-Papilionoideae)

The distribution pattern of calcium oxalate crystals in the leaf, stem, and root of four Nigerian species of Aneilema was investigated and reported for the first time. The histochemically localised crystals of calcium oxalate varied in shape and region of localisation depending on the vegetative part of these Aneilema species. In the leaf of these taxa, crystals were found in the basal cells of trichomes (A aequinoctiale, A. beniniense and A. umbrosum) and in the mesophyll region of the lamina. Variations in shape were apparent in the stem: rhomboidal (A. aequinoctiale and A. beniniense) and irregular (A. paludosum and A. umbrosum). The diversity in localisation and shape of calcium oxalate crystals among these investigated species of Aneilema is discussed in relation to their biological significance.

N.O. Ogbebor

Papers

Distribution of calcium oxalate crystals in some Nigerian species of Aneilema R. Br. (Commelinaceae)