Phytochemical investigation of Teucrium pruinosum and biological potential assessment of the isolated diterpenoids

Authors: AYDOGAN, FADIME - University Of Mississippi; BOGA, MEHMET - University Of Mississippi; KHAN, SHABANA - University Of Mississippi; ZULFIQAR, FAZILA - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi; ALI, ZULFIQAR - University Of Mississippi

Submitted to: Biochemical Systematics and Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2022
Publication Date: 11/15/2022
Citation: Aydogan, F., Boga, M., Khan, S.I., Zulfiqar, F., Khan, I.A., Ali, Z. 2022. Phytochemical investigation of Teucrium pruinosum and biological potential assessment of the isolated diterpenoids. Biochemical Systematics and Ecology, Volume 105, 2022, 104545, https://doi.org/10.1016/j.bse.2022.104545.
DOI: https://doi.org/10.1016/j.bse.2022.104545

Interpretive Summary: Teucrium L. is one of the largest, cosmopolitan, and polymorphic members of the Ajugoideae subfamily in Lamiaceae. Teucrium comprises about 300 species mainly distributed in Europe, Asia, and North Africa. Teucrium species are generally perennial, herbaceous shrubs/subshrubs, with trichome-type calyxes, and characteristic corollas with reduced upper lips. The Mediterranean region is the main genetic speciation center of Teucrium L. This genus is represented by 50 taxa (38 species) in the flora of Turkey and its endemism ratio is 38 %. Teucrium species have been used in folk medicine for treating various ailments such as diabetes, rheumatism, inflammation, gastric, digestive, and respiratory disorders, abscesses, gout, conjunctivitis, and tuberculosis, as well as in the stimulation of fat and cellulite decomposition. Infusions of aerial parts of Teucrium species can also be used as a diuretic, antipyretic, tonic, diaphoretic, analgesic, and antihyperlipidemic. Over 300 compounds have been reported from this genus, mainly highly oxidized neo-clerodane diterpenoids, and to a lesser extent rearranged abietane diterpenoids. Neo-clerodane type diterpenoids have been reported to possess various biological activities such as antibacterial, anti-inflammatory, antioxidative, anticancer, antimicrobial, antidiabetic, antinociceptive, anticholinesterase, and anthelminthic. This study reports a detailed phytochemical investigation of T. pruinosum together with in-vitro antimicrobial, anti-inflammatory, and antiplasmodial activity assessment of the isolated diterpenoids, as well as the chemotaxonomic significance of the isolated compounds.

Technical Abstract: Twenty-three compounds of diverse classes including iridoid glycosides (1'3), phenylethanoids (4 and 14), neo-clerodane diterpenoids (5'9), abietene diterpenoids (10'12), sesquiterpenoids (13), steroids (15), and flavonoids (16'23) were isolated from the whole plant Teucrium pruinosum. Their structures were determined by analysis of spectoscopic data. The diterpenoids (5'12) were tested for antimicrobial, antiplasmodial, and anti-inflammatory activities. 7-O-acetylhorminone (10) showed significant activity against chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 values of 7.1 and 12.0 µM, respectively, and anti-inflammatory activity via iNOS inhibition with an IC50 value of 0.55± 0.07 µM. This is the first report regarding the chemical constituents and biological activities of T. pruinosum. The chemotaxonomic significance of the isolated compounds is discussed.