Ten new and four known clerodane diterpenoids were isolated from the vine and leaves of Tinospora crispa. The chemical structures and absolute stereochemical configurations of all the compounds were established...
Purpose: To isolate, purify and determine the antioxidant property of total flavonoids from the roots of Ardisia mamillata, so as to provide a theoretical basis for development of natural antioxidants. Methods: Macroporous resin was used to optimize the isolation and purification of total flavonoids, taking adsorption rate and resolution rate as evaluation indices. The antioxidant property of the purified total flavonoids was determined using 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6trinitrophenyl)hydrazyl (DPPH) radical scavenging activity. Results: The best conditions for separation and purification of total flavonoids from Ardisia mamillata roots were: use of ADS-7 resin, loading total flavonoid concentration of 0.8896 mg/mL, loading buffer flow rate of 1.5 mL/min, loading buffer pH of 4.48, elution ethanol concentration of 60 %, and flow rate of 2.5 mL/min. Under these conditions, the degree of purification of total flavonoids of Ardisia mamillata root was 76.43 ± 0.36 %, adsorption rate was 96.52 ± 0.19 %, while resolution rate was 99.31 ± 0.27 %. When the concentration of the purified total flavonoids was 4.0 mg/mL, its DPPH radical scavenging activity was stronger than that of the standard, butylated hydroxytoluene (BHT), but lower than that of vitamin C. Conclusion: ADS-7 resin is the best macroporous resin for the purification of total flavonoids from the radix of Ardisia mamillata Hance, under the optimized conditions. The purified total flavonoids of Ardisia mamillata root have stronger DPPH radical scavenging ability than the standard, BHT.
Five new polychlorinated bibenzyls (1–5) along with 3 known compounds (6–8) were isolated from the stems and leaves of Rhododendronminutiflorum. The chemical structures of all the isolates were determined by spectroscopic methods, and compounds 1 and 2 were further verified by single-crystal X-ray diffraction analyses. Compounds 1–5 were halogenated compounds which bear three to five chlorine atoms in their chemical structures. Biologically, compounds 2, 5 and 6 showed varying degrees of toxicity toward the Asian citrus psyllid (Diaphorinacitri) with LD50 values 27.15, 17.02 and 16.20 mg/L, respectively. These values were comparable to the positive control matrine (LD50 = 11.86 mg/L), which were calculated using observations on day 6. Meanwhile, compound 4 had α-glucosidase inhibitory activity with IC50 value of 17.87 ± 0.74 μM.
Graphical Abstract
The tuberous root of Tinospora sagittata (Oliv.) Gagnep is the
original plant of Traditional Chinese Medicine Tinosporae Radix
(“Jin Guo Lan”), which usually be used to treat pharyngeal arthralgia,
carbuncle furuncle, bacillary dysentery, abdominal pain and
inflammation. Twenty-six clerodane diterpenoids were isolated from
T. sagittata, including 8 new clerodane diterpenoids (tinotanoid
A-H: 1-8), and 18 known ones (9-26).
The absolute configurations of compounds 1, 2,
5, 8, 13, 17 and 20 were
determined by single-crystal X-ray diffraction. Compound 1 is
the first example of clerodane diterpenoid with a γ lactone ring
which were constructed between C-11 and C-17. Compound 2 and
17 is a pair of epimer. Compounds 2, 12 and
17 showed excellent inhibitory activity on NO production with
IC50 values of 9.56±0.69, 9.11±0.53 and 11.12±0.70 μM, respectively, and
the activities were significantly stronger than the positive control
Minocycline (Mino) (IC50 value was 23.57±0.92 μM). Moreover, compounds
2, 12 and 17 dramatically reduced the expressions of
iNOS and COX-2 up-regulated by LPS treatment. Compounds 2 and
12 can significantly inhibit the levels of pro-inflammatory
cytokines TNF-α, IL-1β and IL-6 that are increased by LPS
stimulation.
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