Nutritional and functional components of mulberry leaves from different varieties: Evaluation of their potential as food materials

Figures & data

Table 1. Crude protein, crude fiber, total soluble sugars, and DNJ content in dried mulberry leaves from 19 varieties.

Variety	crude protein (g/100 g DW)	crude fiber (g/100 g DW)	total soluble sugar (mg/g DW)	DNJ (mg/g DW)
D10	28.29 ± 0.15^k	12.41 ± 0.05^i	118.29 ± 2.95^b	0.16 ± 0.04^n
DHS	29.56 ± 0.29^i	14.92 ± 0.72^bcd	87.89 ± 1.68^g	1.03 ± 0.07^c
GS8	27.97 ± 0.31^kl	11.46 ± 0.08^j	150.31 ± 4.12^a	0.08 ± 0.01°
HYS	37.36 ± 0.59^a	15.30 ± 0.25^bc	71.58 ± 1.37^l	0.50 ± 0.01^h
HM	33.5 ± 0.34^de	12.20 ± 0.59^ij	76.69 ± 2.29^ijk	0.31 ± 0.01^kl
JTHY	33.75 ± 0.01^d	14.58 ± 0.18^cde	77.91 ± 0.30^ij	0.67 ± 0.00^g
LYD	32.82 ± 0.39^f	12.34 ± 0.26^i	78.81 ± 1.37^i	0.35 ± 0.01^j
LJ504	32.27 ± 0.62^g	15.10 ± 0.47^bc	77.76 ± 1.55^ij	0.29 ± 0.00^l
NS14	33.38 ± 0.67^de	14.10 ± 0.36^def	111.32 ± 0.61^c	1.07 ± 0.02^b
QS1	32.91 ± 0.03^f	15.27 ± 0.02^bc	74.95 ± 0.25^jk	0.84 ± 0.00^e
TP2	33.44 ± 0.47^de	15.08 ± 0.10^bc	66.78 ± 1.36^m	1.12 ± 0.05^a
TS	29.83 ± 0.13^i	13.09 ± 0.71^ghi	92.59 ± 1.23^f	0.30 ± 0.01^l
X7920	31.5 ± 0.36^h	13.90 ± 0.40^efg	81.21 ± 0.30^h	0.34 ± 0.00^jk
XGS	33.17 ± 0.21^ef	13.01 ± 0.47^hi	58.71 ± 1.21^n	0.49 ± 0.02^h
XYZL	29.02 ± 0.08^j	13.35 ± 0.14^fgh	65.33 ± 2.00^m	0.81 ± 0.04^f
XG	36.42 ± 0.33^b	15.01 ± 0.25^bc	74.45 ± 2.98^k	0.98 ± 0.05^d
XS	27.63 ± 0.06^l	12.22 ± 0.46^ij	102.65 ± 4.23^d	0.24 ± 0.00^m
Y237	31.88 ± 0.16^gh	16.61 ± 0.42^a	93.53 ± 3.37^f	0.43 ± 0.02^i
ZS5801	34.19 ± 0.17^c	15.50 ± 0.22^b	98.89 ± 4.03^e	0.28 ± 0.00^l

Values are Mean ± SD, n = 3 ((three independent extractions). Average in rows marked with different letters differ significantly (P < 0.05).

Table 2. Phenolics and flavonoids content (mg/g DW) in mulberry leaves from 19 varieties.

Variety	TP	TF	CHA	RU	IQT	QMG	AG	KMG
D10	15.2 ± 0.19^c	42.85 ± 2.19^c	6.24 ± 0.31^cd	2.13 ± 0.10^b	3.50 ± 0.17^b	0.68 ± 0.03^k	1.32 ± 0.06^a	ND^h
DHS	10.68 ± 0.15^g	32.28 ± 0.51^efg	3.86 ± 0.05^fg	0.56 ± 0.06^hij	1.14 ± 0.04^ij	1.88 ± 0.14^ef	0.35 ± 0.01^jk	0.46 ± 0.01^g
GS8	20.26 ± 0.07^a	56.41 ± 2.02^a	10.24 ± 0.06^a	4.31 ± 0.01^a	4.83 ± 0.01^a	1.16 ± 0.01^j	1.10 ± 0.00^b	ND^h
HYS	11.77 ± 0.63^f	35.15 ± 2.34^de	3.31 ± 0.19^g	0.66 ± 0.01^gh	1.20 ± 0.01^hi	1.39 ± 0.03^i	0.46 ± 0.00^fgh	0.57 ± 0.01^f
HM	10.37 ± 0.01^g	26.44 ± 0.09^ij	3.71 ± 0.23^fg	0.99 ± 0.09^e	1.32 ± 0.07^gh	1.71 ± 0.04^fg	0.53 ± 0.01^e	0.66 ± 0.05^e
JTHY	11.55 ± 0.15^f	30.00 ± 1.57^gh	4.65 ± 0.16^e	0.75 ± 0.04^fg	1.38 ± 0.06^g	2.43 ± 0.11^cd	0.52 ± 0.02^e	0.82 ± 0.03^c
LYD	12.82 ± 0.07^e	37.31 ± 0.18^d	5.96 ± 0.28^d	1.04 ± 0.04^e	1.41 ± 0.07^g	2.71 ± 0.09^b	0.52 ± 0.02^e	0.81 ± 0.04^cd
LJ504	11.75 ± 0.02^f	31.12 ± 0.22^fgh	3.70 ± 0.01^fg	0.84 ± 0.01^f	1.28 ± 0.02^gh	1.48 ± 0.03^hi	0.49 ± 0.00^efg	0.56 ± 0.01^f
NS14	16.05 ± 0.25^b	48.17 ± 0.27^b	7.44 ± 0.06^b	2.01 ± 0.04^c	1.81 ± 0.05^f	2.76 ± 0.13^b	0.51 ± 0.02^ef	0.82 ± 0.02^cd
QS1	8.76 ± 0.01^h	25.30 ± 0.22^ij	4.65 ± 0.16^e	0.58 ± 0.01^hij	0.77 ± 0.03^m	2.25 ± 0.07^d	0.41 ± 0.02^hi	0.75 ± 0.02^d
TP2	9.03 ± 0.30^h	24.03 ± 0.39^jk	2.45 ± 0.03^h	0.42 ± 0.02^k	0.70 ± 0.03^m	1.01 ± 0.04^j	0.34 ± 0.00^jk	0.46 ± 0.00^g
TS	11.88 ± 0.05^f	31.64 ± 4.30^fgh	6.69 ± 0.56^c	0.66 ± 0.00^gh	2.16 ± 0.00^d	3.05 ± 0.00^a	0.70 ± 0.00^d	1.03 ± 0.00^b
X7920	12.59 ± 0.06^e	34.38 ± 3.01^def	4.12 ± 0.52^f	0.45 ± 0.04^k	1.01 ± 0.09^jk	1.93 ± 0.22^e	0.42 ± 0.03^hi	0.67 ± 0.05^e
XGS	10.28 ± 0.01^g	26.22 ± 3.62^ij	4.02 ± 0.06^f	0.55 ± 0.04^ij	0.95 ± 0.09^kl	2.01 ± 0.18^e	0.45 ± 0.03^gh	0.78 ± 0.06^cd
XYZL	10.45 ± 0.32^g	28.59 ± 1.12^hi	3.92 ± 0.23^f	0.55 ± 0.00^ij	1.03 ± 0.02^jk	2.31 ± 0.01^d	0.30 ± 0.05^k	0.76 ± 0.01^cd
XG	8.87 ± 0.11^h	21.36 ± 1.53^k	2.56 ± 0.17^h	0.50 ± 0.02^jk	0.83 ± 0.04^lm	1.60 ± 0.07^gh	0.38 ± 0.01^ij	0.57 ± 0.02^f
XS	15.31 ± 0.09^c	41.22 ± 2.51^c	4.86 ± 0.02^e	0.98 ± 0.03^e	1.96 ± 0.00^e	1.57 ± 0.01^ghi	0.74 ± 0.00^d	0.69 ± 0.00^e
Y237	10.68 ± 0.11^g	28.42 ± 0.49^hi	3.35 ± 0.01^g	0.64 ± 0.00^hi	0.94 ± 0.00^kl	1.15 ± 0.04^j	0.44 ± 0.01^h	0.51 ± 0.02^fg
ZS5801	14.78 ± 0.53^d	43.03 ± 1.37^c	5.84 ± 0.33^d	1.15 ± 0.04^d	2.34 ± 0.08^c	2.56 ± 0.09^bc	0.92 ± 0.03^c	1.19 ± 0.04^a

Values are Mean ± SD, n = 3 ((three independent extractions). Average in rows marked with different letters differ significantly (P < 0.05).

Abbreviations: TP, total phenolics; TF, totalflavonoids; DW, dry weight; GAE, gallic acid equivalent; RE, rutin equivalent; CHA, chlorogenic acid; RU, rutin; IQT, isoquercitrin; QMG, quercetin-malonyl-glucoside; AG, astragalin; KMG, kaempferol-malonyl-glucoside; ND, not detected.

Table 3. Antioxidant activities determined by FRAP, DPPH, and ABTS methods and resulting antioxidant composite index (ACI) in mulberry leaves from 19 varieties.

Variety	DPPH (μmol TE/g DW)	ABTS (μmol TE/g DW)	FRAP (μmolAAE/g DW)	ACI	Ranking
D10	54.17 ± 1.49^a	65.20 ± 1.02^def	138.37 ± 6.69^bc	93.27	3
DHS	36.03 ± 1.22^de	51.62 ± 2.15^j	102.82 ± 7.71^fgh	67.83	17
GS8	56.37 ± 0.60^a	70.84 ± 0.94^a	149.15 ± 4.05^a	100.00	1
HYS	42.16 ± 0.57^c	62.42 ± 2.81^fgh	129.43 ± 6.46^c	83.56	8
HM	38.22 ± 1.07^d	59.07 ± 0.49^i	104.33 ± 4.60^efg	73.93	12
JTHY	47.10 ± 1.93^b	68.21 ± 0.49^abc	114.06 ± 1.73^de	85.12	7
LYD	38.19 ± 1.60^d	67.46 ± 1.23^bcd	117.19 ± 3.50^d	80.60	10
LJ504	38.75 ± 2.38^d	63.11 ± 0.54^efg	112.76 ± 8.45^edf	77.41	11
NS14	46.72 ± 0.96^b	69.03 ± 0.80^ab	147.97 ± 2.55^ab	92.19	4
QS1	33.22 ± 2.73^e	52.09 ± 3.12^j	105.28 ± 3.56^efg	67.59	18
TP2	33.81 ± 0.78^c	65.10 ± 1.59^def	102.18 ± 5.62^fgh	73.31	13
TS	46.48 ± 3.09^b	62.33 ± 0.44^fgh	132.66 ± 8.76^c	86.26	6
X7920	36.00 ± 1.07^de	65.48 ± 1.33^cde	129.70 ± 7.47^c	80.75	9
XGS	37.95 ± 2.53^d	61.01 ± 2.51^ghi	97.21 ± 9.13^gh	73.16	15
XYZL	37.96 ± 0.60^d	59.89 ± 1.33^hi	99.96 ± 3.04^gh	72.21	16
XG	34.15 ± 1.04^e	51.28 ± 1.20^j	91.62 ± 6.17^h	64.82	19
XS	46.18 ± 1.16^b	69.13 ± 1.81^ab	129.84 ± 4.54^c	88.10	5
Y237	33.27 ± 1.49^e	64.93 ± 1.94^def	101.75 ± 9.44^fgh	73.21	14
ZS5801	54.65 ± 1.19^a	69.13 ± 1.88^ab	132.53 ± 2.64^a	94.35	2

Mean ± SD of three measurements. Average in rows marked with different letters differ significantly (P < 0.05).

Table 4. Analysis of the correlation between total polyphenol content and in vitro antioxidation activity of mulberry leaves.

TAC	TP	TF	CHA	RU	IQT	QMG	AG	KMG
DPPH	0.840**	0.812**	0.775**	0.726**	0.878**	0.029	0.879**	−0.124
ABTS	0.712**	0.669**	0.528*	0.489*	0.516*	−0.004	0.502*	0.001
FRAP	0.881**	0.899**	0.799**	0.689**	0.758**	0.075	0.703**	−0.127
ACI	0.913**	0.898**	0.799**	0.721**	0.821**	0.049	0.794**	−0.101

** indicated significant correlation at 0.01 level (two-sided), * indicated significant correlation at 0.05 level (two-sided).

Table 5. Loading matrix eigenvector and cumulative contributionrate of healthcare function evaluation factors of mulberry leaf.

Index	Factor 1	Factor 2
TP	0.960	−0.067
TF	0.945	−0.017
CHA	0.955	0.153
RU	0.907	−0.294
IQT	0.942	−0.250
QMG	0.038	0.978
AG	0.827	−0.267
KMG	−0.263	0.922
Contribution rate/%	64.860	25.682
Cumulative contribution rate/%	64.860	90.541

Extration method: principal component analysis

Rotation method: Varimax with Kaiser Normalization component scores

Figure 1. The principal component analysis (PCA) showing correlation of phenolic profiles with PC1 and PC2.

Table 6. Analysis of the correlation between the organic compounds.

	CP	CF	TSS	DNJ	TP	TF
CP	1	0.551*	−0.539*	0.356	−0.467*	−0.420
CF		1	−0.38	0.482*	−0.513*	−0.436
TSS			1	−0.426	0.894**	0.838**
DNJ				1	−0.532*	−0.444
TP					1	0.980**
TF						1

** indicated significant correlation at 0.01 level (two-sided), * indicated significant correlation at 0.05 level (two-sided).

Abbreviations: CP, crude protein; CF, crude fiber; TSS, total soluble sugars; DNJ, 1-deoxynojirimycin; TP, total phenolics; TF, total flavonoids.

Figure 2. Dendrogram of cluster analysis based on the content of crude protein (CP), total soluble sugars (TSS), crude fiber (CF), total phenolics (TP), total flavonoid (TF) and DNJ of mulberry leaves.