Neuroprotective effects of alkaloids from Piper longum in a MPTP-induced mouse model of Parkinson’s disease

Figures & data

Figure 1. HPLC fingerprint of PLA at 254 nm. (1) Piperlonguminine, (2) piperanine, (3) piperine, and (4) pellitorine.

Figure 2. Behavioral performance tested in open-field test. (A1) Total distance of different groups of mice in the open field from 1 d to 28 d (*p < 0.05 versus control; #p < 0.05 versus model). (A2) Total distance of different groups of mice in the open field from 35 d to 56 d (*p < 0.05 versus control; #p < 0.05 versus model). (B1) Total time of different groups of mice in the open field from 1 d to 28 d (s) (*p < 0.05 versus control; #p < 0.05 versus model). (B2) Total time of different groups of mice in the open field from 35 d to 56 d (s) (*p < 0.05 versus control; #p < 0.05 versus model). Data are expressed as mean ± SD (N_{Model group} = 14, N_{Other groups} = 12).

Table 1. Transmitter contents (ng/g wet brain tissue; mean ± SD) in the striatum analyzed by UFLC-ESI-MS/MS.

	DA	DOPAC	HVA	5-HT	5-HIAA	Ach	GABA
Control	835.2 ± 19.2^a	613.3 ± 200.0^a	225.0 ± 30.0	21.3 ± 0.95#	56.2 ± 20.3^a	378.2 ± 51.4	20 611 ± 3551^a
Model	204.8 ± 6.4^b	118.6 ± 64.0^b	240.3 ± 38.8	15.9 ± 1.26*	91.3 ± 19.4^b	392.0 ± 67.5	27 824 ± 5124^b
PLA-Pr	486.4 ± 148.8^a	485.3 ± 106.2^a	308.0 ± 77.7	19.8 ± 4.2#	74.3 ± 25.3	395.5 ± 46.9	21 987 ± 2172^a
PLA-120	401.6 ± 86.4^a	290.0 ± 17.6#	291.8 ± 31.3	16.4 ± 1.0	60.9 ± 11.2#	361.6 ± 69.3	25 091 ± 3141
PLA-60	306.1 ± 25.9#	376 ± 75.6^a	294.4 ± 43.1	17.2 ± 4.8	80.8 ± 13.8	364.2 ± 31.7	24 573 ± 1385
PLA-30	255.0 ± 20.8#	267.2 ± 71.5	240.8 ± 9.2	17.5 ± 4.4	80.2 ± 18.2	394.6 ± 80.0	21 936 ± 3105.6#
Piperine	355.2 ± 52.8^a	703.4 ± 132.9^a	297.6 ± 43.1	14.0 ± 0.37	63.2 ± 26.9#	430.4 ± 13.6	23 692.8 ± 740.8#
Madorpar	285.6 ± 33.2^a	291.7 ± 4.6	317.9 ± 53.3	18.3 ± 0.9#	82.0 ± 33.9	352.4 ± 32.7	31 472 ± 1986

N = 6, ^ap < 0.01 and #p < 0.05 versus model; ^bp < 0.01 and *p < 0.05 versus control.

Figure 3. (A) The photographs of the protective effects of PLA on the MPTP-induced loss of tyrosine hydroxylase (TH)-immunoreactive neurons in the substantia nigral pars compacta (SNpc). (a1 and a2) The control group (n = 12); (b1 and b2) the model group (n = 14); (c1 and c2) the PLA prevention group (n = 12); (d1–f2) PLA (120, 60, and 30 mg/mL) treated plus MPTP-injected groups (n = 12); (g1 and g2) piperine (60 mg/mL) treated plus MPTP-injected group (n = 12); (h1 and h2) the Madopar group (n = 12). (B) The number of TH-immunoreactive neurons in the SNpc of the different groups (*p < 0.05 and **p < 0.01 versus control; #p < 0.05 and ##p < 0.01 versus model).

Figure 4. The contents of TH expression in different groups detected by Western blot. β-Actin was used as the internal control. Results were expressed as mean ± SD (N_{Model group} = 14, N_{Other groups} = 12, *p < 0.05 and **p < 0.01 versus control; #p < 0.05 and ##p < 0.01 versus model).

Figure 5. The levels of glutathione (GSH), superoxide dismutase (SOD), and malondiadehycle (MDA) in different groups. (A) GSH, (B) SOD, and (C) MDA (N = 9, *p < 0.05 and **p < 0.01 versus control; #p < 0.05 and ##p < 0.01 versus model).