LAUSR

Asparagus burjaticus Peschkova (Asparagaceae) is a perennial species occurring in Russia only in forest-steppe regions of southern Republic of Buryatia and belongs to the series Foliati (species with developed cladodes), subsection Leptantheri in the phylogenetically young section Neoasparagus, genus Asparagus [1]. Roots of A. burjaticus in Tibetan medicine (nye shing) and other Asparagus species (A. dauricus, A. filicinus, A. racemosus) were used as decoctions and tonics to increase lifespan and for female, lymphatic, renal, and skin diseases [2]. Buryat lamas used fruit of A. burjaticus (pan bras) for heart defects [3]. It is recommended in Mongolian medicine as a diuretic [4]. Chemical studies of this species have not been reported. Therefore, the present work studied the compositions of triterpenoids and phenolic compounds from aerial and subterranean organs of A. burjaticus. Plants of A. burjaticus were collected in the Republic of Buryatia (in the vicinity of Shaluty, Tarbagatai District, July 11, 2017, Sept. 6, 2017; 51°35′4.72′′ N, 107°23′5.54′′ E; h = 574 m above sea level). Specimens of the raw material are preserved in the herbarium of the IGEB, SB, RAS (No. As/th-17/07-25/0007, As/th-17/09-25/0082). The species was determined by Dr. N. K. Chirikova (North-Eastern Federal University, Yakutsk, Russia). Raw material was air-dried in the shade to moisture ≤5% and milled to particle size 1−2 mm. Column chromatography (CC) used polyamide, silica gel (SiO2), and Sephadex LH-20 (Sigma-Aldrich, St. Louis, MO, USA). Spectrophotometric studies used an SF-2000 spectrophotometer (OKB Spectr, St. Petersburg, Russia). Mass spectrometric studies used an LCMS-8050 TQ mass spectrometer (Shimadzu, Columbia, MD, USA). The conditions were published [5, 6]. Preparative conditions were HPLC-1: LiChrospher® 100 RP-18 column (250 × 10 mm, ∅ 10 μm; Dionex, Sunnyvale, CA, USA), eluent A, H2O, eluent B, MeCN; gradient program 0−20 min, 10−20%B, 20−60 min, 20−100%B, 60−64 min, 100%B, flow rate 2 mL/min, column temperature 30°C; prep. HPLC-2: Zorbax Rx-SIL column (250 × 4.6 mm, ∅ 5 μm; Agilent Technologies, Santa Clara, CA, USA); CH2Cl2i-PrOH−H2O eluent, 125:25:1; flow rate 1 mL/min, column temperature 40°C; prep. HPLC-3: LiChrospher ® 100 RP-18 column (250 × 10 mm, ∅ 10 μm; Dionex, Sunnyvale, CA, USA); eluent A, H2O, eluent B, MeCN; gradient program 0−60 min, 5−40%B, 60−90 min, 40−70%B; flow rate 2 mL/min, column temperature 45°C. Extraction and Fractionation. Ground cladodes of A. burjaticus (collection date July 11, 2017; 2.5 kg) were extracted (3×) with EtOH (70%, 1:20) in an ultrasonic bath (100 W, 35 kHz) at 50°C for 2 h. The combined extract was evaporated to dryness, suspended in H2O (1:5), and extracted with hexane, EtOAc, and BuOH. EtOAc fraction A1 (65.5 g) was chromatographed over polyamide (CC, 5 × 50 cm, H2O−EtOH−NH3, 100:0:0→10:90:0→10:89.5:0.5) to give fractions A1-1 (H2O), A1-2 (H2O−EtOH, 60:40), A1-3 (H2O−EtOH, 20:80), and A1-4 (H2O−EtOH−NH3, 10:89.5:0.5). Fraction A1-1 was suspended in H2O (1:5) and extracted with EtOAc−Me2CO (9:1). The organic extract was chromatographed over SiO2 (CC, 3 × 50 cm, EtOAc−Me2CO, 100:0→50:50) and then using prep. HPLC-1 and prep. HPLC-2 conditions to afford 20-hydroxyecdysone-3-O-glucoside (11 mg, 1) [7]; 20-hydroxyecdysone (18 mg, 2) [8]; and polypodine B (4 mg, 3) [9]. Fraction A1-2 was separated over SiO2 (CC, 2 × 40 cm, EtOAc−EtOH, 100:0→70:30) to isolate four compounds including isoquercitrin (32 mg, 4) [10], narcissin (19 mg, 5) [10], astragalin (12 mg, 6) [11], and isorhamnetin-3-O-glucoside (14 mg, 7) [12]. Fraction A1-4 after CC over Sephadex LH-20 (2 × 70 cm, EtOH−H2O, 90:10→40:60) afforded 4-O-caffeoylquinic acid (25 mg, 8) [13], 5-O-caffeoylquinic acid (20 mg, 9) [14], 1,3-di-O-caffeoylquinic acid (14 mg, 10) [13], and 3,5-di-Ocaffeoylquinic acid (8 mg, 11) [12].