Service:
postCliente(cliente: Clientes){
        let bodypost = JSON.stringify(cliente);
        let headers = new Headers({'Content-Type':'application/json'});
        return this._http.post(this.url+'clientes',bodypost,{headers:headers})
            .map(res => res.json())
            .catch((err:Response)=> Observable.throw(err.json()));
    }

Interface:
export interface Clientes {
    cemail: string;
    cpassword: string;
    cnombre: string;
    capellidos: string;
    ctelefono: string;
    activo: string;
}

Component:
import { ActivatedRoute, Router } from '@angular/router/';
import { ClientesService } from '../clientes.service';
import { Clientes } from '../clientes';
import { Component, OnInit, ViewEncapsulation, Input } from '@angular/core';
import { FormsModule } from '@angular/forms';

@Component({
  selector: 'kp-cliente',
  templateUrl: './cliente.component.html',
  styleUrls: ['./cliente.component.css'],
  providers:[ClientesService]
})
export class ClienteComponent implements OnInit {
    public opcioncliente: string;
    public isRequired: boolean;
    public isDisabled: boolean;
    public isDisabledMultiple: boolean;
    public itemMultiple: any;
    public Client: string;
    public cliente: Clientes;
    public errorMessage;

  constructor(private _clientesService:ClientesService,
              private _route:ActivatedRoute,
              private _router:Router) {
        this.opcioncliente = 'nuevo cliente';
        this.isRequired = true;
        this.isDisabled = false;
        this.isDisabledMultiple = false;
        this.itemMultiple = null;

  }

  ngOnInit( ) {
    this.cliente = new Clientes("","","","","","");
  }

  public postCliente(){
    console.log(this.cliente);
    this._clientesService.postCliente(this.cliente).subscribe(
      response=> {
            if(!response.cliente){
                alert(`Error al guardar nuevo cliente `)
            }else{
            this.cliente = response.cliente;
            }
      },
       error => {
            this.errorMessage = <any>error;
            if(this.errorMessage != null){
                console.log(this.errorMessage);
                alert(`Error al conseguir los clientes ${this.errorMessage}`);
            }
        }

    )
  }
}